Use this worksheet to help students master mental math by extending basic multiplication and addition facts to larger numbers with zeros.

Let’s solve each problem step by step. We’ll start with the simple facts, then use them to build up to the bigger ones — all in our head!

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First column:

1. 4 × 7 = ?
Think: 4 groups of 7 → 7 + 7 + 7 + 7 = 28
✔ Answer: 28

2. 40 × 7 = ?
Think: 40 is 4 tens → so 4 tens × 7 = 28 tens → 280
✔ Answer: 280

3. 40 + 70 = ?
Think: 4 tens + 7 tens = 11 tens → 110
✔ Answer: 110

4. 400 + 70 = ?
Think: 400 + 70 = 470 (just add 70 to 400)
✔ Answer: 470

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Second column:

5. 6 × 8 = ?
Think: 6 groups of 8 → 8 + 8 + 8 + 8 + 8 + 8 = 48
✔ Answer: 48

6. 60 + 8 = ?
Think: 60 + 8 = 68
✔ Answer: 68

7. 60 + 80 = ?
Think: 6 tens + 8 tens = 14 tens → 140
✔ Answer: 140

8. 600 + 80 = ?
Think: 600 + 80 = 680
✔ Answer: 680

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Third column:

9. 9 × 5 = ?
Think: 9 groups of 5 → 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 = 45
✔ Answer: 45

10. 90 × 5 = ?
Think: 90 is 9 tens → 9 tens × 5 = 45 tens → 450
✔ Answer: 450

11. 90 + 50 = ?
Think: 9 tens + 5 tens = 14 tens → 140
✔ Answer: 140

12. 900 × 500 = ?
Think: 9 × 5 = 45, and we have two zeros from 900 and two from 500 → total 4 zeros → 45 followed by 4 zeros = 450,000
✔ Answer: 450,000

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Fourth column:

13. 8 × 2 = ?
Think: 8 + 8 = 16
✔ Answer: 16

14. 8 × 20 = ?
Think: 8 × 2 = 16, then add one zero → 160
✔ Answer: 160

15. 80 × 20 = ?
Think: 8 × 2 = 16, and two zeros total (one from 80, one from 20) → 1600
✔ Answer: 1600

16. 800 × 20 = ?
Think: 8 × 2 = 16, and three zeros total (two from 800, one from 20) → 16,000
✔ Answer: 16,000

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Fifth column:

17. 3 × 6 = ?
Think: 3 groups of 6 → 6 + 6 + 6 = 18
✔ Answer: 18

18. 3 × 60 = ?
Think: 3 × 6 = 18, then add one zero → 180
✔ Answer: 180

19. 300 × 60 = ?
Think: 3 × 6 = 18, and three zeros total (two from 300, one from 60) → 18,000
✔ Answer: 18,000

20. 300 × 600 = ?
Think: 3 × 6 = 18, and four zeros total (two from each) → 180,000
✔ Answer: 180,000

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Sixth column:

21. 5 × 9 = ?
Think: same as 9 × 5 → 45
✔ Answer: 45

22. 5 × 90 = ?
Think: 5 × 9 = 45, add one zero → 450
✔ Answer: 450

23. 500 × 9 = ?
Think: 5 × 9 = 45, add two zeros → 4,500
✔ Answer: 4,500

24. 5,000 × 9,000 = ?
Think: 5 × 9 = 45, and six zeros total (three from each) → 45 followed by 6 zeros = 45,000,000
✔ Answer: 45,000,000

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Final Answer:
4 × 7 = 28
40 × 7 = 280
40 + 70 = 110
400 + 70 = 470

6 × 8 = 48
60 + 8 = 68
60 + 80 = 140
600 + 80 = 680

9 × 5 = 45
90 × 5 = 450
90 + 50 = 140
900 × 500 = 450,000

8 × 2 = 16
8 × 20 = 160
80 × 20 = 1,600
800 × 20 = 16,000

3 × 6 = 18
3 × 60 = 180
300 × 60 = 18,000
300 × 600 = 180,000

5 × 9 = 45
5 × 90 = 450
500 × 9 = 4,500
5,000 × 9,000 = 45,000,000