Multiply by Multiples of 10 - 3rd Grade Math

1. What is $2 \times 50$?

   $100$. Multiply $2 \times 5 = 10$, then add a zero.

2. What place-value strategy can you use to find $6\times 70$ quickly?

   Compute $6\times 7=42$, then write $420$. Multiply the single digits first, then add a zero for the tens place.

3. What is $9\times 80$?

   $720$. Since $9 \times 8 = 72$, add one zero to get $9 \times 80 = 720$.

4. What is $7\times 60$?

   $420$. Since $7 \times 6 = 42$, add one zero to get $7 \times 60 = 420$.

5. What is $7 \times 60$?

   $420$. Calculate $7 \times 6 = 42$, then append one zero.

6. What is $6 \times 70$?

   $420$. Calculate $6 \times 7 = 42$, then append one zero.

7. What is $4 \times 30$?

   $120$. Multiply $4 \times 3 = 12$, then add a zero.

8. What is $8 \times 40$?

   $320$. Multiply $8 \times 4 = 32$, then add a zero.

9. What is $7\times 30$?

   $210$. Since $7 \times 3 = 21$, add one zero to get $7 \times 30 = 210$.

10. What is $1 \times 70$?

    $70$. Any number times 1 equals itself.

11. What is $9 \times 20$?

    $180$. Calculate $9 \times 2 = 18$, then append one zero.

12. What is $4 \times 80$?

    $320$. Multiply $4 \times 8 = 32$, then add a zero.

13. What is $3 \times 90$?

    $270$. Multiply $3 \times 9 = 27$, then add a zero.

14. Find the missing number: $8\times 50=\square$.

    $400$. Since $8 \times 5 = 40$, add one zero to get $8 \times 50 = 400$.

15. What property justifies $7\times 40=40\times 7$?

    Commutative property of multiplication. Order doesn't matter when multiplying two numbers.

16. What is $8 \times 90$?

    $720$. Multiply $8 \times 9 = 72$, then add a zero.

17. What is $4 \times 90$?

    $360$. Calculate $4 \times 9 = 36$, then append one zero.

18. What is $6\times 70$?

    $420$. Since $6 \times 7 = 42$, add one zero to get $6 \times 70 = 420$.

19. What is $8\times 40$?

    $320$. Since $8 \times 4 = 32$, add one zero to get $8 \times 40 = 320$.

20. What is $3\times 70$?

    $210$. Since $3 \times 7 = 21$, add one zero to get $3 \times 70 = 210$.

21. What is $8\times 90$?

    $720$. Since $8 \times 9 = 72$, add one zero to get $8 \times 90 = 720$.

22. What is $2 \times 90$?

    $180$. Calculate $2 \times 9 = 18$, then append one zero.

23. What is $9 \times 80$?

    $720$. Calculate $9 \times 8 = 72$, then append one zero.

24. What is $6 \times 50$?

    $300$. Multiply $6 \times 5 = 30$, then add a zero.

25. What is $5 \times 90$?

    $450$. Multiply $5 \times 9 = 45$, then add a zero.

26. Identify the correct product: $9 \times 50 = \ ?$

    $450$. Multiply $9 \times 5 = 45$, then add a zero.

27. What is $0 \times 70$?

    $0$. Zero times any number equals zero.

28. Find and correct the error: $3 \times 80 = 2400$.

    Correct: $3 \times 80 = 240$. The extra zero was incorrectly added; $3 \times 8 = 24$ plus one zero.

29. Which expression is equivalent to $4 \times 60$: $4 \times 6 \times 10$ or $4 \times 10 \times 60$?

    $4 \times 6 \times 10$. Break 60 into $6 \times 10$ to use place value strategy.

30. What is $5\times 60$?

    $300$. Since $5 \times 6 = 30$, add one zero to get $5 \times 60 = 300$.

31. Identify the correct product: $9\times 30$ equals what?

    $270$. Since $9 \times 3 = 27$, add one zero to get $9 \times 30 = 270$.

32. What is $1 \times 80$?

    $80$. Any number times 1 equals itself.

33. What is $3\times 50$?

    $150$. Since $3 \times 5 = 15$, add one zero to get $3 \times 50 = 150$.

34. What is $9 \times 30$?

    $270$. Multiply $9 \times 3 = 27$, then add a zero.

35. What is $3 \times 40$?

    $120$. Calculate $3 \times 4 = 12$, then append one zero.

36. Find $4\times 70$ using $4\times 7$ and place value. What is the product?

    $280$. Since $4 \times 7 = 28$, add one zero to get $4 \times 70 = 280$.

37. What is $5 \times 30$?

    $150$. Calculate $5 \times 3 = 15$, then append one zero.

38. What is $8 \times 50$?

    $400$. Calculate $8 \times 5 = 40$, then append one zero.

39. What is $9\times 10$?

    $90$. Since $9 \times 1 = 9$, add one zero to get $9 \times 10 = 90$.

40. What is $4\times 90$?

    $360$. Since $4 \times 9 = 36$, add one zero to get $4 \times 90 = 360$.

41. What is $6\times 20$?

    $120$. Since $6 \times 2 = 12$, add one zero to get $6 \times 20 = 120$.

42. State the commutative property for multiplication using $6 \times 70$ as the example.

    $6 \times 70 = 70 \times 6$. Order doesn't matter in multiplication.

43. What is $5\times 90$?

    $450$. Since $5 \times 9 = 45$, add one zero to get $5 \times 90 = 450$.

44. What is $7 \times 80$?

    $560$. Multiply $7 \times 8 = 56$, then add a zero.

45. What is $5 \times 70$?

    $350$. Multiply $5 \times 7 = 35$, then add a zero.

46. What is the value of $7 \times 3 \times 10$?

    $210$. Multiply in any order: $7 \times 3 = 21$, then $21 \times 10 = 210$.

47. What is $2\times 80$?

    $160$. Since $2 \times 8 = 16$, add one zero to get $2 \times 80 = 160$.

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