Calculating the value of 3rd grade expressions is one of the basic but important math knowledge and forms that often appear in exams. So, in the following article, Trường THPT Trần Hưng Đạo will share details on how to calculate expression values, along with some common types of exercises with solution methods for you to understand.
Knowledge to remember when calculating the value of 3 grade math expressions
If in the 1st and 2nd grade math curriculum, they are only weak to familiarize themselves with exercises with individual calculations. However, when entering 3rd grade math, they will be familiar with problems that have many calculations put together, requiring them to calculate. This is the “value of the expression”.
The concept of expressions and the value of expressions
In mathematics, numeric expressions are operations and numbers combined. When we solve those calculations, we will get a result called the value of the expression.
So, the value of the expression: The result after performing the calculations in the expression.
Expression types and order of operations
The types of 3rd grade math exercises are quite diverse, especially the expression part will have the following forms and order of execution:
Type 1: Expression containing only operations of the same precedence: Add, subtract or multiply, divide: Perform the calculation from left to right.
Example: Calculate the expression value:
a) 93 : 3 x 7 b) 15 x 7 : 5
Solution guide
a) 93 : 3 x 7 = 31 x 7 = 217
b) 15 x 7 : 5 = 105 : 5 = 21
Form 2: Expressions include addition, subtraction, multiplication, and division, we perform multiplication and division first, addition and subtraction later;
Example: Write the following expressions and evaluate them:
a) Calculate the product of 15 and 4 and then add 42.
b) Calculate the sum of 98 and 37 and then subtract 74.
Solution guide
a) 15 x 4 + 42 = 60 + 42 = 102.
b) 98 + 37 – 74 = 135 – 74 = 61.
Form 3: The expression contains brackets ( ), we will perform the calculation in the brackets first, outside the brackets after.
Example: Calculate the value of the following expressions:
a) 99927 : (10248:8 – 1272)
b) (10356×5 – 780) : 6
Instruct:
a) 99927 : (10248:8 – 1272) = 99927 : (1281 – 1272) = 99927 : 9 = 11103.
b) (10356×5 – 780) : 6 = (51780 – 780) : 6 = 51000 : 6 = 8500
Attention:
Case 1: If the expression with multiplication and division is not adjacent, but between the operations there is a sign of addition or subtraction, we will perform both multiplication and division at the same time. Then continue to consider the signs of the remaining calculations in the expression and apply according to the above expression types.
Example: 128 × 2 + 367 × 3 – 895 + 476 × 4 – 2018 + 182
= 256 + 1101 – 895 + 1904 – 2018 + 182
= 1357 – 895 + 1904 – 2018 + 182
= 462 + 1904 – 2018 + 182
= 2366 – 2018 + 182
= 348 + 182
= 530
Or 128 × 2 + 367 × 3 – 895 + 476 × 4 – 2018 + 182
= 256 + 1101 – 895 + 1904 – 2018 + 182
= 1357 – 895 + 1904 – (2018 – 182)
= 462 + 1904 – 1836
= 2366 – 1836
= 530
Case 2: If the expression has division and multiplication standing next to each other, we will have to do it in order from left to right instead of calculating multiplication first and then division. After that, we will continue to consider the remaining calculation signs in the expression according to the given rules.
Example: 195615 : 945 × 13 – 356 + 1024
= 207 × 13 – 356 + 1024
= 2691 – 356 +1024
= 2335 + 1024
= 3359
Rules for calculating class 3 . expression values
Based on the above expression types, we can draw important rules when calculating the following expression values:
The expression has only 2 operations of addition and subtraction or multiplication and division, we only need to do it in order from left to right.
Expressions including addition, subtraction, multiplication and division, everyone needs to follow the “multiply and divide first, add and subtract later” rule.
In an expression containing brackets (), we will have to do the calculation in the brackets first and then the outside of the brackets.
Instructions for solving grade 3 math textbook exercises to calculate the value of expressions
Here are some exercises in the 3rd grade math program in the textbook with solutions for your reference:
Lesson 1: Calculate the value of the expression: (page 79)
a) 205 + 60 + 30
268 – 68 + 17
b) 462 – 40 + 70
287 – 7 – 80
Solution guide
a) 205 + 60 + 30 = 265 + 30
= 295
268 – 68 + 17 = 200 + 17
= 217
b) 462 – 40 + 70 = 422 + 70
= 492
287 – 7 – 80 = 280 – 80
= 200
Lesson 2: Calculating the value of expressions (page 79)
a) 15 × 3 × 2
48 : 2 : 6
b) 8 × 5 : 2
81 : 9 × 7
Solution guide
a) 15 × 3 × 2 = 45 × 2 = 90
48 : 2 : 6 = 24 : 6 = 4
b) 8 × 5 : 2 = 40 : 2 = 20
81 : 9 × 7 = 9 × 7 = 63
Lesson 3: (page 79) Fill in the <; >; = enter the following dot
55 × 5: 3 …. 32
47 ….. 84 – 34 – 3
20 + 5 ….. 40 : 2 + 6
Solution guide
55 × 5 : 3 > 32
47 = 84 -34 – 3
20 + 5 < 40 : 2 + 6
Lesson 4 (page 79) Each pack of noodles weighs 80g, each milk carton weighs 455g. How many grams are 2 packs of noodles and 1 carton of milk?
Solution guide
2 packs of noodles and 1 carton of milk weigh in grams:
80 + 80 + 455 = 615 grams
Answer: 615 grams
Instructions for solving math exercises on page 80 of the textbook:
Lesson 1: (page 80) Calculate the value of the expression:
a) 253 + 10 × 4
41 × 5 – 100
93 – 48 : 8
b) 500 + 6 × 7
30 × 8 + 50
69 + 20 × 4
Solution guide
a) 253 + 10 × 4 = 253 + 40 = 293
41 × 5 − 100 = 205 – 100 = 105
93 – 48 : 8 = 93 – 6 = 87
b) 500 + 6 × 7 = 500 + 42 = 542
30 × 8 + 50 = 240 + 50 = 290
69 + 20 × 4 = 69 + 80 = 149
Lesson 2: (page 80) Fill in the following blanks with true or false
a) 37 – 5 × 5 = 12
180 : 6 + 30 = 60
30 + 60 × 2 = 150
282 – 100 : 2 = 91
b) 13 × 3 – 2 = 13
180 + 30 : 6 = 35
10 + 60 × 2 = 180
282 – 100 : 2 = 232
Solution guide
a) 37 – 5 × 5 = 12 RED
180 : 6 + 30 = 60 RED
30 + 60 × 2 = 150 RED
282 – 100 : 2 = 91 SHO
b) 13 × 3 – 2 = 13 W
180 + 30 : 6 = 35 W
10 + 60 × 2 = 180 W
282 – 100 : 2 = 232 RED
Lesson 3: (page 80) Mother picked 60 apples, sister picked 35 apples. Mother’s and sister’s apples are placed in 5 boxes. How many apples are there in each box?
Solution guide
The total number of apples picked by mother and sister is:
60 + 35 = 95 (fruit)
The number of apples in each box is:
95 : 5 = 19 (fruit)
Exercises to calculate the value of expressions 3rd grade apply
In addition to the exercise of calculating expression values in the 3rd grade math textbook, below Trường THPT Trần Hưng Đạo will summarize some more related exercises so that students can apply their knowledge to practice effectively:
Exercise 1: Calculate the value of the following expressions:
150 + 10 x 3 =
40 x 5 – 125 =
90 – 48 : 8 =
135 + 7 x 6 =
69 + 20 : 5 =
132 + 5 x (7 + 8) =
Exercise 2: Write (T) True (T), false (S) in the following blanks:
32 – 5 x 5 = 7
180 : 6 + 35 = 75
30 + 60 x 2 = 150
282 – 82 : 2 = 100
30 + 20 x 2 = 80
131 – 32 x 3 = 25
Exercise 3: Two friends Nam and Huy go to pick apples in the garden. Nam picked 30 fruits, Huy picked 10 less than Nam. The number of apples you picked are evenly distributed into 5 boxes. How many apples does each box contain?
Exercise 4: Fill in the blanks below with appropriate signs (>, =, <)
135 + 5 x 3…. 125 + 5 x 5
189 : 3 x 8 …. 189 : 9 x 8
12 + 20 x 2…. 16 + 50 : 2
156 + 20 : 2 …. 156 + 5x 2
145 : 3 + 10 …. 145 – 20 x 2
Exercise 5:
a) (563+ 126) x 2
b) 4 x 108 + 157 =
c)1243 – 366 : 3
d)435 : 5 + 582 =
e)153 + 638 – 470 =
Exercise 6: Calculate the value of the expression:
a. 3 x (89424 – 72813)
b. 24368 + 15336 : 3
c. 72009 : 3 x 2
d. 2 x 45000 : 9
e. 15 840 + 32046 : 7
f. 32 464 : 8 – 3956
g. 15 840 + 8972 x 6
i. (12 879 – 9 876) x 4
H. 239 + 1267 x 3=
l. 2505 : ( 403 – 398)=
Exercise 7: Calculate the value of the expression:
( 4672 + 3583 ) : 5
1956 + 2126 x 4
4672 – ( 3583 – 193)
2078 – 3328 : 4
Exercise 8: Write an expression and then calculate the value of the expression:
a. 45 divided by 5 multiplied by 7
b. 1535 divided by 5 plus 976
c. 236 multiplied by 2 minus 195
d. 1562 divided by 3 times 4
Exercise 9: Calculate the value of the following expressions
a) 78 x 6 + 345 c) 56 + 67 x 6
b) 378 + 324 : 3 d) 288 : 6 x 7
Exercise 10. 25x4x7; 216×3 : 6; 990 :3 : 6; 480 :8 x 7; 125×2:5
Experience conquering 3rd grade math to calculate expression value
For children who have just entered grade 3, solving math problems with many combined calculations will certainly be more difficult than solving math problems like grade 1 and grade 2. So, to help children conquer this form of math more easily and effectively, here are some experiences for them to refer to and apply.
Build a math foundation with Trường THPT Trần Hưng Đạo Math
Calculating class 3 expression values is basically the same as regular operations. So, to make it easier for children to understand and be more interested in learning 3rd grade math, don’t ignore the Trường THPT Trần Hưng Đạo Math tool. This is an online thinking math teaching application for children from preschool to primary school, with the content built closely following the Ministry’s latest educational program. Thereby helping children to build a solid mathematical foundation, while supporting learning math knowledge in school better.
Trường THPT Trần Hưng Đạo Math. (Photo: Trường THPT Trần Hưng Đạo)” >
The special feature of Trường THPT Trần Hưng Đạo Math is that it applies many different teaching methods to help children feel more excited instead of just transmitting ordinary knowledge like school. Include:
Applying active teaching methods: Stimulating creativity, children actively ask questions to understand the root of the problem given in Mathematics.
Learning through games: Play while learning with outstanding efficiency. Children are interested, self-directed learning without parents reminding.
Learning with supplementary workbooks: Help your child develop fine and gross motor skills through solving real-world problems.
After completing the course with Trường THPT Trần Hưng Đạo Math, it will help children:
Develop 5 Math competencies under the new General Education program & form logical thinking habits from an early age
Develop thinking & intelligence during the golden period of brain development
Building a Math foundation & supporting effective classroom learning
Synchronous development of thinking & language helps children learn well in both math and English
To better understand Trường THPT Trần Hưng Đạo Math, parents can refer to the following video or register for detailed advice:
Mastering the rules for calculating the value of the expression
To calculate the value of an expression, it is required that you know the 3 rules mentioned above. Parents can explain each rule in detail for children to understand, regularly check their children’s old knowledge to make sure to avoid the situation of “learning first, forgetting later”.
Do the exercises, practice often
Regular practice and practice is considered the best method to support knowledge improvement, especially for young children. After knowing the rules and understanding how to solve the real value calculation exercise, parents should let their children practice regularly, do related exercises every day, or participate in games, solve puzzles, participate in competitions on the internet, etc.
Through regular training, children’s brains will work better, improve calculation skills and promote more carefulness when learning effectively.
Teaching experience to calculate the value of expressions through mathematical thinking
Mental math is considered a learning method that combines many skills. In addition to solving exercises in books, parents can combine with solving math problems related to practice and visual aids. Thereby, it will help increase the child’s receptivity and interest in conquering math problems more effectively.
Conclude
Above are the sharing of knowledge about calculating the value of 3rd grade expressions so that children and their parents can refer to, as well as accompany their children on the way to conquer this subject and knowledge. If parents plan to learn about tools to help their children learn math more effectively, don’t ignore Trường THPT Trần Hưng Đạo Math.
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Calculating the value of 3rd grade expressions is one of the basic but important math knowledge and forms that often appear in exams. So, in the following article, Trường THPT Trần Hưng Đạo will share details on how to calculate expression values, along with some common types of exercises with solution methods for you to understand.
Knowledge to remember when calculating the value of 3 grade math expressions
If in the 1st and 2nd grade math curriculum, they are only weak to familiarize themselves with exercises with individual calculations. However, when entering 3rd grade math, they will be familiar with problems that have many calculations put together, requiring them to calculate. This is the "value of the expression".
The concept of expressions and the value of expressions
In mathematics, numeric expressions are operations and numbers combined. When we solve those calculations, we will get a result called the value of the expression.
So, the value of the expression: The result after performing the calculations in the expression.
Expression types and order of operations
The types of 3rd grade math exercises are quite diverse, especially the expression part will have the following forms and order of execution:
Type 1: Expression containing only operations of the same precedence: Add, subtract or multiply, divide: Perform the calculation from left to right.
Example: Calculate the expression value:
a) 93 : 3 x 7 b) 15 x 7 : 5
Solution guide
a) 93 : 3 x 7 = 31 x 7 = 217
b) 15 x 7 : 5 = 105 : 5 = 21
Form 2: Expressions include addition, subtraction, multiplication, and division, we perform multiplication and division first, addition and subtraction later;
Example: Write the following expressions and evaluate them:
a) Calculate the product of 15 and 4 and then add 42.
b) Calculate the sum of 98 and 37 and then subtract 74.
Solution guide
a) 15 x 4 + 42 = 60 + 42 = 102.
b) 98 + 37 - 74 = 135 - 74 = 61.
Form 3: The expression contains brackets ( ), we will perform the calculation in the brackets first, outside the brackets after.
Example: Calculate the value of the following expressions:
a) 99927 : (10248:8 – 1272)
b) (10356×5 – 780) : 6
Instruct:
a) 99927 : (10248:8 – 1272) = 99927 : (1281 - 1272) = 99927 : 9 = 11103.
b) (10356×5 – 780) : 6 = (51780 - 780) : 6 = 51000 : 6 = 8500
Attention:
Case 1: If the expression with multiplication and division is not adjacent, but between the operations there is a sign of addition or subtraction, we will perform both multiplication and division at the same time. Then continue to consider the signs of the remaining calculations in the expression and apply according to the above expression types.
Example: 128 × 2 + 367 × 3 - 895 + 476 × 4 - 2018 + 182
= 256 + 1101 - 895 + 1904 - 2018 + 182
= 1357 - 895 + 1904 - 2018 + 182
= 462 + 1904 - 2018 + 182
= 2366 - 2018 + 182
= 348 + 182
= 530
Or 128 × 2 + 367 × 3 - 895 + 476 × 4 - 2018 + 182
= 256 + 1101 - 895 + 1904 - 2018 + 182
= 1357 - 895 + 1904 - (2018 - 182)
= 462 + 1904 - 1836
= 2366 - 1836
= 530
Case 2: If the expression has division and multiplication standing next to each other, we will have to do it in order from left to right instead of calculating multiplication first and then division. After that, we will continue to consider the remaining calculation signs in the expression according to the given rules.
Example: 195615 : 945 × 13 - 356 + 1024
= 207 × 13 - 356 + 1024
= 2691 - 356 +1024
= 2335 + 1024
= 3359
Rules for calculating class 3 . expression values
Based on the above expression types, we can draw important rules when calculating the following expression values:
The expression has only 2 operations of addition and subtraction or multiplication and division, we only need to do it in order from left to right.
Expressions including addition, subtraction, multiplication and division, everyone needs to follow the "multiply and divide first, add and subtract later" rule.
In an expression containing brackets (), we will have to do the calculation in the brackets first and then the outside of the brackets.
Instructions for solving grade 3 math textbook exercises to calculate the value of expressions
Here are some exercises in the 3rd grade math program in the textbook with solutions for your reference:
Lesson 1: Calculate the value of the expression: (page 79)
a) 205 + 60 + 30
268 – 68 + 17
b) 462 – 40 + 70
287 – 7 – 80
Solution guide
a) 205 + 60 + 30 = 265 + 30
= 295
268 – 68 + 17 = 200 + 17
= 217
b) 462 – 40 + 70 = 422 + 70
= 492
287 – 7 – 80 = 280 – 80
= 200
Lesson 2: Calculating the value of expressions (page 79)
a) 15 × 3 × 2
48 : 2 : 6
b) 8 × 5 : 2
81 : 9 × 7
Solution guide
a) 15 × 3 × 2 = 45 × 2 = 90
48 : 2 : 6 = 24 : 6 = 4
b) 8 × 5 : 2 = 40 : 2 = 20
81 : 9 × 7 = 9 × 7 = 63
Lesson 3: (page 79) Fill in the <; >; = enter the following dot
55 × 5: 3 …. 32
47 ….. 84 – 34 – 3
20 + 5 ..... 40 : 2 + 6
Solution guide
55 × 5 : 3 > 32
47 = 84 -34 – 3
20 + 5 < 40 : 2 + 6
Lesson 4 (page 79) Each pack of noodles weighs 80g, each milk carton weighs 455g. How many grams are 2 packs of noodles and 1 carton of milk?
Solution guide
2 packs of noodles and 1 carton of milk weigh in grams:
80 + 80 + 455 = 615 grams
Answer: 615 grams
Instructions for solving math exercises on page 80 of the textbook:
Lesson 1: (page 80) Calculate the value of the expression:
a) 253 + 10 × 4
41 × 5 – 100
93 – 48 : 8
b) 500 + 6 × 7
30 × 8 + 50
69 + 20 × 4
Solution guide
a) 253 + 10 × 4 = 253 + 40 = 293
41 × 5 − 100 = 205 – 100 = 105
93 – 48 : 8 = 93 – 6 = 87
b) 500 + 6 × 7 = 500 + 42 = 542
30 × 8 + 50 = 240 + 50 = 290
69 + 20 × 4 = 69 + 80 = 149
Lesson 2: (page 80) Fill in the following blanks with true or false
a) 37 – 5 × 5 = 12
180 : 6 + 30 = 60
30 + 60 × 2 = 150
282 – 100 : 2 = 91
b) 13 × 3 – 2 = 13
180 + 30 : 6 = 35
10 + 60 × 2 = 180
282 – 100 : 2 = 232
Solution guide
a) 37 – 5 × 5 = 12 RED
180 : 6 + 30 = 60 RED
30 + 60 × 2 = 150 RED
282 – 100 : 2 = 91 SHO
b) 13 × 3 – 2 = 13 W
180 + 30 : 6 = 35 W
10 + 60 × 2 = 180 W
282 – 100 : 2 = 232 RED
Lesson 3: (page 80) Mother picked 60 apples, sister picked 35 apples. Mother's and sister's apples are placed in 5 boxes. How many apples are there in each box?
Solution guide
The total number of apples picked by mother and sister is:
60 + 35 = 95 (fruit)
The number of apples in each box is:
95 : 5 = 19 (fruit)
Exercises to calculate the value of expressions 3rd grade apply
In addition to the exercise of calculating expression values in the 3rd grade math textbook, below Trường THPT Trần Hưng Đạo will summarize some more related exercises so that students can apply their knowledge to practice effectively:
Exercise 1: Calculate the value of the following expressions:
150 + 10 x 3 =
40 x 5 – 125 =
90 – 48 : 8 =
135 + 7 x 6 =
69 + 20 : 5 =
132 + 5 x (7 + 8) =
Exercise 2: Write (T) True (T), false (S) in the following blanks:
32 – 5 x 5 = 7
180 : 6 + 35 = 75
30 + 60 x 2 = 150
282 – 82 : 2 = 100
30 + 20 x 2 = 80
131 – 32 x 3 = 25
Exercise 3: Two friends Nam and Huy go to pick apples in the garden. Nam picked 30 fruits, Huy picked 10 less than Nam. The number of apples you picked are evenly distributed into 5 boxes. How many apples does each box contain?
Exercise 4: Fill in the blanks below with appropriate signs (>, =, <)
135 + 5 x 3…. 125 + 5 x 5
189 : 3 x 8 …. 189 : 9 x 8
12 + 20 x 2…. 16 + 50 : 2
156 + 20 : 2 …. 156 + 5x 2
145 : 3 + 10 …. 145 – 20 x 2
Exercise 5:
a) (563+ 126) x 2
b) 4 x 108 + 157 =
c)1243 – 366 : 3
d)435 : 5 + 582 =
e)153 + 638 – 470 =
Exercise 6: Calculate the value of the expression:
a. 3 x (89424 – 72813)
b. 24368 + 15336 : 3
c. 72009 : 3 x 2
d. 2 x 45000 : 9
e. 15 840 + 32046 : 7
f. 32 464 : 8 – 3956
g. 15 840 + 8972 x 6
i. (12 879 – 9 876) x 4
H. 239 + 1267 x 3=
l. 2505 : ( 403 – 398)=
Exercise 7: Calculate the value of the expression:
( 4672 + 3583 ) : 5
1956 + 2126 x 4
4672 – ( 3583 – 193)
2078 – 3328 : 4
Exercise 8: Write an expression and then calculate the value of the expression:
a. 45 divided by 5 multiplied by 7
b. 1535 divided by 5 plus 976
c. 236 multiplied by 2 minus 195
d. 1562 divided by 3 times 4
Exercise 9: Calculate the value of the following expressions
a) 78 x 6 + 345 c) 56 + 67 x 6
b) 378 + 324 : 3 d) 288 : 6 x 7
Exercise 10. 25x4x7; 216×3 : 6; 990 :3 : 6; 480 :8 x 7; 125×2:5
Experience conquering 3rd grade math to calculate expression value
For children who have just entered grade 3, solving math problems with many combined calculations will certainly be more difficult than solving math problems like grade 1 and grade 2. So, to help children conquer this form of math more easily and effectively, here are some experiences for them to refer to and apply.
Build a math foundation with Trường THPT Trần Hưng Đạo Math
Calculating class 3 expression values is basically the same as regular operations. So, to make it easier for children to understand and be more interested in learning 3rd grade math, don't ignore the Trường THPT Trần Hưng Đạo Math tool. This is an online thinking math teaching application for children from preschool to primary school, with the content built closely following the Ministry's latest educational program. Thereby helping children to build a solid mathematical foundation, while supporting learning math knowledge in school better.
Trường THPT Trần Hưng Đạo Math. (Photo: Trường THPT Trần Hưng Đạo)" >
The special feature of Trường THPT Trần Hưng Đạo Math is that it applies many different teaching methods to help children feel more excited instead of just transmitting ordinary knowledge like school. Include:
Applying active teaching methods: Stimulating creativity, children actively ask questions to understand the root of the problem given in Mathematics.
Learning through games: Play while learning with outstanding efficiency. Children are interested, self-directed learning without parents reminding.
Learning with supplementary workbooks: Help your child develop fine and gross motor skills through solving real-world problems.
After completing the course with Trường THPT Trần Hưng Đạo Math, it will help children:
Develop 5 Math competencies under the new General Education program & form logical thinking habits from an early age
Develop thinking & intelligence during the golden period of brain development
Building a Math foundation & supporting effective classroom learning
Synchronous development of thinking & language helps children learn well in both math and English
To better understand Trường THPT Trần Hưng Đạo Math, parents can refer to the following video or register for detailed advice:
Mastering the rules for calculating the value of the expression
To calculate the value of an expression, it is required that you know the 3 rules mentioned above. Parents can explain each rule in detail for children to understand, regularly check their children's old knowledge to make sure to avoid the situation of "learning first, forgetting later".
Do the exercises, practice often
Regular practice and practice is considered the best method to support knowledge improvement, especially for young children. After knowing the rules and understanding how to solve the real value calculation exercise, parents should let their children practice regularly, do related exercises every day, or participate in games, solve puzzles, participate in competitions on the internet, etc.
Through regular training, children's brains will work better, improve calculation skills and promote more carefulness when learning effectively.
Teaching experience to calculate the value of expressions through mathematical thinking
Mental math is considered a learning method that combines many skills. In addition to solving exercises in books, parents can combine with solving math problems related to practice and visual aids. Thereby, it will help increase the child's receptivity and interest in conquering math problems more effectively.
Conclude
Above are the sharing of knowledge about calculating the value of 3rd grade expressions so that children and their parents can refer to, as well as accompany their children on the way to conquer this subject and knowledge. If parents plan to learn about tools to help their children learn math more effectively, don't ignore Trường THPT Trần Hưng Đạo Math.
[rule_{ruleNumber}]
[box type=”note” align=”” class=”” ltr”>Knowledge to remember when calculating the value of 3 grade math expressions
If in the 1st and 2nd grade math curriculum, they are only weak to familiarize themselves with exercises with individual calculations. However, when entering 3rd grade math, they will be familiar with problems that have many calculations put together, requiring them to calculate. This is the “value of the expression”.
The concept of expressions and the value of expressions
In mathematics, numeric expressions are operations and numbers combined. When we solve those calculations, we will get a result called the value of the expression.
So, the value of the expression: The result after performing the calculations in the expression.
Expression types and order of operations
The types of 3rd grade math exercises are quite diverse, especially the expression part will have the following forms and order of execution:
Type 1: Expression containing only operations of the same precedence: Add, subtract or multiply, divide: Perform the calculation from left to right.
Example: Calculate the expression value:
a) 93 : 3 x 7 b) 15 x 7 : 5
Solution guide
a) 93 : 3 x 7 = 31 x 7 = 217
b) 15 x 7 : 5 = 105 : 5 = 21
Form 2: Expressions include addition, subtraction, multiplication, and division, we perform multiplication and division first, addition and subtraction later;
Example: Write the following expressions and evaluate them:
a) Calculate the product of 15 and 4 and then add 42.
b) Calculate the sum of 98 and 37 and then subtract 74.
Solution guide
a) 15 x 4 + 42 = 60 + 42 = 102.
b) 98 + 37 – 74 = 135 – 74 = 61.
Form 3: The expression contains brackets ( ), we will perform the calculation in the brackets first, outside the brackets after.
Example: Calculate the value of the following expressions:
a) 99927 : (10248:8 – 1272)
b) (10356×5 – 780) : 6
Instruct:
a) 99927 : (10248:8 – 1272) = 99927 : (1281 – 1272) = 99927 : 9 = 11103.
b) (10356×5 – 780) : 6 = (51780 – 780) : 6 = 51000 : 6 = 8500
Attention:
Case 1: If the expression with multiplication and division is not adjacent, but between the operations there is a sign of addition or subtraction, we will perform both multiplication and division at the same time. Then continue to consider the signs of the remaining calculations in the expression and apply according to the above expression types.
Example: 128 × 2 + 367 × 3 – 895 + 476 × 4 – 2018 + 182
= 256 + 1101 – 895 + 1904 – 2018 + 182
= 1357 – 895 + 1904 – 2018 + 182
= 462 + 1904 – 2018 + 182
= 2366 – 2018 + 182
= 348 + 182
= 530
Or 128 × 2 + 367 × 3 – 895 + 476 × 4 – 2018 + 182
= 256 + 1101 – 895 + 1904 – 2018 + 182
= 1357 – 895 + 1904 – (2018 – 182)
= 462 + 1904 – 1836
= 2366 – 1836
= 530
Case 2: If the expression has division and multiplication standing next to each other, we will have to do it in order from left to right instead of calculating multiplication first and then division. After that, we will continue to consider the remaining calculation signs in the expression according to the given rules.
Example: 195615 : 945 × 13 – 356 + 1024
= 207 × 13 – 356 + 1024
= 2691 – 356 +1024
= 2335 + 1024
= 3359
Rules for calculating class 3 . expression values
Based on the above expression types, we can draw important rules when calculating the following expression values:
The expression has only 2 operations of addition and subtraction or multiplication and division, we only need to do it in order from left to right.
Expressions including addition, subtraction, multiplication and division, everyone needs to follow the “multiply and divide first, add and subtract later” rule.
In an expression containing brackets (), we will have to do the calculation in the brackets first and then the outside of the brackets.
Instructions for solving grade 3 math textbook exercises to calculate the value of expressions
Here are some exercises in the 3rd grade math program in the textbook with solutions for your reference:
Lesson 1: Calculate the value of the expression: (page 79)
a) 205 + 60 + 30
268 – 68 + 17
b) 462 – 40 + 70
287 – 7 – 80
Solution guide
a) 205 + 60 + 30 = 265 + 30
= 295
268 – 68 + 17 = 200 + 17
= 217
b) 462 – 40 + 70 = 422 + 70
= 492
287 – 7 – 80 = 280 – 80
= 200
Lesson 2: Calculating the value of expressions (page 79)
a) 15 × 3 × 2
48 : 2 : 6
b) 8 × 5 : 2
81 : 9 × 7
Solution guide
a) 15 × 3 × 2 = 45 × 2 = 90
48 : 2 : 6 = 24 : 6 = 4
b) 8 × 5 : 2 = 40 : 2 = 20
81 : 9 × 7 = 9 × 7 = 63
Lesson 3: (page 79) Fill in the <; >; = enter the following dot
55 × 5: 3 …. 32
47 ….. 84 – 34 – 3
20 + 5 ….. 40 : 2 + 6
Solution guide
55 × 5 : 3 > 32
47 = 84 -34 – 3
20 + 5 < 40 : 2 + 6
Lesson 4 (page 79) Each pack of noodles weighs 80g, each milk carton weighs 455g. How many grams are 2 packs of noodles and 1 carton of milk?
Solution guide
2 packs of noodles and 1 carton of milk weigh in grams:
80 + 80 + 455 = 615 grams
Answer: 615 grams
Instructions for solving math exercises on page 80 of the textbook:
Lesson 1: (page 80) Calculate the value of the expression:
a) 253 + 10 × 4
41 × 5 – 100
93 – 48 : 8
b) 500 + 6 × 7
30 × 8 + 50
69 + 20 × 4
Solution guide
a) 253 + 10 × 4 = 253 + 40 = 293
41 × 5 − 100 = 205 – 100 = 105
93 – 48 : 8 = 93 – 6 = 87
b) 500 + 6 × 7 = 500 + 42 = 542
30 × 8 + 50 = 240 + 50 = 290
69 + 20 × 4 = 69 + 80 = 149
Lesson 2: (page 80) Fill in the following blanks with true or false
a) 37 – 5 × 5 = 12
180 : 6 + 30 = 60
30 + 60 × 2 = 150
282 – 100 : 2 = 91
b) 13 × 3 – 2 = 13
180 + 30 : 6 = 35
10 + 60 × 2 = 180
282 – 100 : 2 = 232
Solution guide
a) 37 – 5 × 5 = 12 RED
180 : 6 + 30 = 60 RED
30 + 60 × 2 = 150 RED
282 – 100 : 2 = 91 SHO
b) 13 × 3 – 2 = 13 W
180 + 30 : 6 = 35 W
10 + 60 × 2 = 180 W
282 – 100 : 2 = 232 RED
Lesson 3: (page 80) Mother picked 60 apples, sister picked 35 apples. Mother’s and sister’s apples are placed in 5 boxes. How many apples are there in each box?
Solution guide
The total number of apples picked by mother and sister is:
60 + 35 = 95 (fruit)
The number of apples in each box is:
95 : 5 = 19 (fruit)
Exercises to calculate the value of expressions 3rd grade apply
In addition to the exercise of calculating expression values in the 3rd grade math textbook, below Trường THPT Trần Hưng Đạo will summarize some more related exercises so that students can apply their knowledge to practice effectively:
Exercise 1: Calculate the value of the following expressions:
150 + 10 x 3 =
40 x 5 – 125 =
90 – 48 : 8 =
135 + 7 x 6 =
69 + 20 : 5 =
132 + 5 x (7 + 8) =
Exercise 2: Write (T) True (T), false (S) in the following blanks:
32 – 5 x 5 = 7
180 : 6 + 35 = 75
30 + 60 x 2 = 150
282 – 82 : 2 = 100
30 + 20 x 2 = 80
131 – 32 x 3 = 25
Exercise 3: Two friends Nam and Huy go to pick apples in the garden. Nam picked 30 fruits, Huy picked 10 less than Nam. The number of apples you picked are evenly distributed into 5 boxes. How many apples does each box contain?
Exercise 4: Fill in the blanks below with appropriate signs (>, =, <)
135 + 5 x 3…. 125 + 5 x 5
189 : 3 x 8 …. 189 : 9 x 8
12 + 20 x 2…. 16 + 50 : 2
156 + 20 : 2 …. 156 + 5x 2
145 : 3 + 10 …. 145 – 20 x 2
Exercise 5:
a) (563+ 126) x 2
b) 4 x 108 + 157 =
c)1243 – 366 : 3
d)435 : 5 + 582 =
e)153 + 638 – 470 =
Exercise 6: Calculate the value of the expression:
a. 3 x (89424 – 72813)
b. 24368 + 15336 : 3
c. 72009 : 3 x 2
d. 2 x 45000 : 9
e. 15 840 + 32046 : 7
f. 32 464 : 8 – 3956
g. 15 840 + 8972 x 6
i. (12 879 – 9 876) x 4
H. 239 + 1267 x 3=
l. 2505 : ( 403 – 398)=
Exercise 7: Calculate the value of the expression:
( 4672 + 3583 ) : 5
1956 + 2126 x 4
4672 – ( 3583 – 193)
2078 – 3328 : 4
Exercise 8: Write an expression and then calculate the value of the expression:
a. 45 divided by 5 multiplied by 7
b. 1535 divided by 5 plus 976
c. 236 multiplied by 2 minus 195
d. 1562 divided by 3 times 4
Exercise 9: Calculate the value of the following expressions
a) 78 x 6 + 345 c) 56 + 67 x 6
b) 378 + 324 : 3 d) 288 : 6 x 7
Exercise 10. 25x4x7; 216×3 : 6; 990 :3 : 6; 480 :8 x 7; 125×2:5
Experience conquering 3rd grade math to calculate expression value
For children who have just entered grade 3, solving math problems with many combined calculations will certainly be more difficult than solving math problems like grade 1 and grade 2. So, to help children conquer this form of math more easily and effectively, here are some experiences for them to refer to and apply.
Build a math foundation with Trường THPT Trần Hưng Đạo Math
Calculating class 3 expression values is basically the same as regular operations. So, to make it easier for children to understand and be more interested in learning 3rd grade math, don’t ignore the Trường THPT Trần Hưng Đạo Math tool. This is an online thinking math teaching application for children from preschool to primary school, with the content built closely following the Ministry’s latest educational program. Thereby helping children to build a solid mathematical foundation, while supporting learning math knowledge in school better.
Trường THPT Trần Hưng Đạo Math. (Photo: Trường THPT Trần Hưng Đạo)” >
The special feature of Trường THPT Trần Hưng Đạo Math is that it applies many different teaching methods to help children feel more excited instead of just transmitting ordinary knowledge like school. Include:
Applying active teaching methods: Stimulating creativity, children actively ask questions to understand the root of the problem given in Mathematics.
Learning through games: Play while learning with outstanding efficiency. Children are interested, self-directed learning without parents reminding.
Learning with supplementary workbooks: Help your child develop fine and gross motor skills through solving real-world problems.
After completing the course with Trường THPT Trần Hưng Đạo Math, it will help children:
Develop 5 Math competencies under the new General Education program & form logical thinking habits from an early age
Develop thinking & intelligence during the golden period of brain development
Building a Math foundation & supporting effective classroom learning
Synchronous development of thinking & language helps children learn well in both math and English
To better understand Trường THPT Trần Hưng Đạo Math, parents can refer to the following video or register for detailed advice:
Mastering the rules for calculating the value of the expression
To calculate the value of an expression, it is required that you know the 3 rules mentioned above. Parents can explain each rule in detail for children to understand, regularly check their children’s old knowledge to make sure to avoid the situation of “learning first, forgetting later”.
Do the exercises, practice often
Regular practice and practice is considered the best method to support knowledge improvement, especially for young children. After knowing the rules and understanding how to solve the real value calculation exercise, parents should let their children practice regularly, do related exercises every day, or participate in games, solve puzzles, participate in competitions on the internet, etc.
Through regular training, children’s brains will work better, improve calculation skills and promote more carefulness when learning effectively.
Teaching experience to calculate the value of expressions through mathematical thinking
Mental math is considered a learning method that combines many skills. In addition to solving exercises in books, parents can combine with solving math problems related to practice and visual aids. Thereby, it will help increase the child’s receptivity and interest in conquering math problems more effectively.
Conclude
Above are the sharing of knowledge about calculating the value of 3rd grade expressions so that children and their parents can refer to, as well as accompany their children on the way to conquer this subject and knowledge. If parents plan to learn about tools to help their children learn math more effectively, don’t ignore Trường THPT Trần Hưng Đạo Math.
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