Let's solve each problem step by step using
basic multiplication facts and
place value as instructed.
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Problem 1: 30 × 90 = ?
Break it down:
- 30 = 3 × 10
- 90 = 9 × 10
- So, 30 × 90 = (3 × 10) × (9 × 10) = (3 × 9) × (10 × 10) = 27 × 100 =
2,700
✔ Answer: 2,700
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Problem 2: 40 × 60 = ?
- 40 = 4 × 10
- 60 = 6 × 10
- So, 40 × 60 = (4 × 6) × (10 × 10) = 24 × 100 =
2,400
✔ Answer: 2,400
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Problem 3: 70 × 50 = ?
- 70 = 7 × 10
- 50 = 5 × 10
- So, 70 × 50 = (7 × 5) × (10 × 10) = 35 × 100 =
3,500
✔ Answer: 3,500
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Problem 4: 20 × 80 = ?
- 20 = 2 × 10
- 80 = 8 × 10
- So, 20 × 80 = (2 × 8) × (10 × 10) = 16 × 100 =
1,600
✔ Answer: 1,600
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Problem 5: 80 × ____ = 3,200
We need to find the missing number.
Divide both sides by 80:
- 3,200 ÷ 80 = ?
Break it down:
- 80 = 8 × 10
- 3,200 = 32 × 100
So:
- 3,200 ÷ 80 = (32 × 100) ÷ (8 × 10) = (32 ÷ 8) × (100 ÷ 10) = 4 × 10 =
40
✔ Answer: 40
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Problem 6: 20 × ____ = 600
Find the missing number:
- 600 ÷ 20 = ?
Break it down:
- 600 = 6 × 100
- 20 = 2 × 10
- So: (6 × 100) ÷ (2 × 10) = (6 ÷ 2) × (100 ÷ 10) = 3 × 10 =
30
✔ Answer: 30
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Problem 7: 60 × ____ = 3,600
Find the missing number:
- 3,600 ÷ 60 = ?
Break it down:
- 3,600 = 36 × 100
- 60 = 6 × 10
- So: (36 × 100) ÷ (6 × 10) = (36 ÷ 6) × (100 ÷ 10) = 6 × 10 =
60
✔ Answer: 60
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Problem 8: 50 × ____ = 2,000
Find the missing number:
- 2,000 ÷ 50 = ?
Break it down:
- 2,000 = 20 × 100
- 50 = 5 × 10
- So: (20 × 100) ÷ (5 × 10) = (20 ÷ 5) × (100 ÷ 10) = 4 × 10 =
40
✔ Answer: 40
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✔ Final Answers:
| Problem | Answer |
|--------|--------|
| 1 | 2,700 |
| 2 | 2,400 |
| 3 | 3,500 |
| 4 | 1,600 |
| 5 | 40 |
| 6 | 30 |
| 7 | 60 |
| 8 | 40 |
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🔍 Explanation Summary:
- For multiplying multiples of 10, break numbers into basic facts (e.g., 30 = 3 × 10).
- Multiply the basic facts first, then multiply by powers of 10.
- For missing factors, use division and place value to simplify.
This method helps build understanding of
place value and makes multi-digit multiplication easier.
Parent Tip: Review the logic above to help your child master the concept of envision math grade 4 worksheet.
