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Solving Grade 3 Mathematics on pages 41, 42 of Workbook Volume 2
Solving exercises on pages 41, 42 of Math 3 Workbook Volume 2, book Connecting Knowledge with Life:
Subtraction within 10,000
Activity
Solve Exercise 1 on Page 41 Math Grade 3 Workbook
Problem: Calculate.
Instructions: Subtract numbers from right to left.
Answer:
Solve Exercise 2 on Page 42 Math Grade 3 Workbook
Problem: Set up the calculation and then solve.
Instructions: Arrange the subtraction vertically so that the digits in the same place value are aligned. Perform subtraction by subtracting digits from right to left.
Answer:
Solve Exercise 3 on Page 42 Math Grade 3 Workbook
Problem: The Nile River is the longest river in the world with a length of 6,650 kilometers. The Red River is 1,149 kilometers long. How many kilometers longer is the Nile River than the Red River?
Instructions: To find out how many kilometers longer the Nile River is compared to the Red River, subtract the length of the Red River from the length of the Nile River.
Answer:
The Nile River is longer than the Red River by:
6,650 - 1,149 = 5,501 (km)
Final Answer: 5,501 km.
Practice
1. Solve Exercise 1 on Page 42 of Math Grade 3 Workbook
Problem: Mental calculation (following the example).
Solution Guide: Observe the example then mentally subtract the rounded thousands.
Answer:
a) 7 thousand - 3 thousand = 4 thousand
7,000 - 3,000 = 4,000
b) 8 thousand - 5 thousand = 3 thousand
8,000 - 5,000 = 3,000
c) 9 thousand - 7 thousand = 2 thousand
9,000 - 7,000 = 2,000
d) 10 thousand - 6 thousand = 4 thousand
10,000 - 6,000 = 4,000
2. Solve Exercise 2 on Page 42 of Math Grade 3 Workbook
Problem: Calculate mentally (following the example).
a) 5,200 - 200 = 5,000
b) 3,500 - 1,000 = 2,500
c) 6,700 - 600 = 6,100
d) 8,400 - 6,000 = 2,400
Solution Guide: Observe the example then mentally subtract the rounded hundreds.
Answer:
a) 200 - 200 = 0
5,200 - 200 = 5,000
b) 3,000 - 1,000 = 2,000
3,500 - 1,000 = 2,500
c) 700 - 600 = 100
6,700 - 600 = 6,100
d) 8,000 - 6,000 = 2,000
8,400 - 6,000 = 2,400.
- See also: Solving exercises on pages 44, 45, 46 of Math 3 Workbook Volume 2, book Connecting Knowledge with Life
3. Solve Exercise 3 on Page 42 of Math Grade 3 Workbook
Problem: Set up the calculation and then solve.
Solution:
- Set up: Write the subtraction vertically so that the numbers in the same place value are aligned.
- Calculation: Perform subtraction by subtracting digits from right to left.
Answer:
4. Solve Exercise 4 on Page 42 of Math Grade 3 Workbook
Problem: A truck carries 9,000 liters of oil. The first time, it pumps 2,500 liters of oil into a gas station. The second time, it pumps 2,200 liters of oil into another station. How many liters of oil are left in the truck?
Solution:
Step 1: Find the total liters of oil pumped for both times = Liters of oil pumped first time + Liters of oil pumped second time.
Step 2: Find the remaining liters of oil after both times pumped = Liters of oil in the truck - Total liters of oil pumped for both times.
Answer:
The total liters of oil pumped by the truck for both times are:
2,500 + 2,200 = 4,700 (liters)
The remaining liters of oil in the truck after both times pumped are:
9,000 - 4,700 = 4,300 (liters)
Final Answer: 4,300 liters
With the problem-solving material on pages 41, 42 of Math Grade 3 Workbook Volume 2, book Connecting Knowledge with Life, students can solve all exercises in the book according to the curriculum. They can also refer to other useful materials to study Mathematics better.
