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Solving Math problems for grade 3 on pages 115, 116, 117 of Workbook Volume 2.
Solutions to exercises on pages 115, 116, 117 of Math 3 Workbook Volume 2, Connecting Knowledge with Life textbook:
Reviewing addition and subtraction within the range of 100,000
Practice Set 1
1. Solve Exercise 1 Page 115 Math Workbook Grade 3
Problem: Set up the calculation and then solve.
Guidance for solving:
- Write the calculations vertically so that numbers in the same column align.
- Perform addition and subtraction from right to left.
Answer:
2. Solve Exercise 2 Page 115 Math Workbook Grade 3
Problem: Among the calculations below, which ones result in numbers less than 6,000, and which ones result in numbers greater than 20,000?
Solution Guide: Calculate the result of each operation and then answer the question of the problem.
Answer:
We have:
3,500 + 2,500 = 6,000.
4,956 + 1,000 = 5,956.
15,000 + 6,000 = 21,000.
41,600 - 21,500 = 20,100.
9,850 - 4,000 = 5,850.
Thus, the calculations with results less than 6,000 are: 4,956 + 1,000; 9,850 - 4,000.
Thus, the calculations with results greater than 20,000 are: 41,600 - 21,500; 15,000 + 6,000.
3. Solve Exercise 3 Page 115 Math Workbook Grade 3
Problem: Calculate the value of the expression.
a) 4,569 + 3,721 - 500
b) 9,170 + (15,729 - 7,729)
Solution Guide:
- For expressions involving only addition and subtraction, perform the operations from left to right.
- For expressions containing parentheses, evaluate the operations within the parentheses first.
Answer:
a) 4,569 + 3,721 - 500 = 8,290 - 500
= 7,790.
b) 9,170 + (15,729 - 7,729) = 9,170 + 8,000
= 17,170.
4. Solve Exercise 4 Page 115 Math Workbook Grade 3
Problem: Mai spent 28,000 dong on a teddy bear and 3,000 dong on glue. She gave the saleswoman 50,000 dong. How much money did the saleswoman return to Mai?
Solution Guide:
Step 1: Calculate the amount Mai spent on purchases.
Step 2: Calculate the amount the saleswoman returns.
Answer:
Mai spent a total of:
28,000 + 3,000 = 31,000 (dong)
So, the amount the saleswoman returns to Mai is:
50,000 - 31,000 = 19,000 (dong)
The answer: 19,000 dong.
5. Solve Exercise 5 Page 115 Math Workbook Grade 3
Exercise 1 Page 116 Mathematics Workbook Grade 3
Problem: Set up and solve the following calculations.
Solution Guide:
Write the calculations vertically so that numbers in the same column are aligned.
Perform addition and subtraction of numbers sequentially from right to left.
Answer:
2. Solve Exercise 2 Page 116 Mathematics Workbook Grade 3
Problem: Choose the correct answers.
Solution Guide:
a) To find the sum of two numbers, perform addition: 6,735 + 3,627.
b) To find the difference between two numbers, perform subtraction: 24,753 - 16,238.
c) For expressions involving only addition and subtraction, calculate from left to right.
Answer:
3. Solve Exercise 3 Page 116 Mathematics Workbook Grade 3
Problem: D, S?
a) The distance from the park entrance to the zoo is closer to the circus than to the animal farm. .......
b) The distance from the park entrance to the zoo is farther from the circus than from the animal farm. .......
Solution Guide:
Step 1: Calculate the distance from the park entrance to the zoo and the distance from the park entrance to the circus.
Step 2: Compare the two distances and fill in the appropriate D, S in the blank spaces.
Answer:
The distance from the park entrance to the circus is: 590 + 450 = 1,040 (m).
The distance from the park entrance to the zoo is: 400 + 280 + 370 = 1,050 (m).
Since 1,040 is less than 1,050 m, the route from the park entrance to the zoo is farther from the circus.
We fill in as follows:
a) S
b) D
4. Solve Exercise 4 Page 117 Mathematics Workbook Grade 3
Problem: A preventive health center received 35,800 doses of COVID-19 vaccine. In the first round, 16,400 doses of vaccine were used, and in the second round, 17,340 doses were used. How many doses of COVID-19 vaccine are left at the health center after the two rounds of use?
Solution Guide:
- Find the total number of doses used in both rounds.
- Find the remaining doses by subtracting the doses used in both rounds from the initial number of doses.
Answer:
The total number of doses used in both rounds is:
16,400 + 17,340 = 33,740 (doses)
The number of doses remaining after the second round is:
35,800 - 33,740 = 2,060 (doses)
Answer: 2,060 doses of vaccine.
Explore the math challenge from Page 117 of Math Textbook for Grade 3.
Question: King Ly Thai To moved the capital from Hoa Lu to Dai La, renaming it Thang Long in 1010. How many years have passed since then?
Solution: Subtract 1010 from the current year to find the number of years since the capital relocation.
Answer: The capital relocation by King Ly Thai To occurred 1012 years ago.
Detailed solutions for exercises on pages 115, 116, and 117 of Math Grade 3 Workbook Volume 2, Connecting Knowledge with Life, are now available. Hope you understand and perform the exercises to the best of your ability.
