Determine Unknown Whole Numbers - 1st Grade Math

1. What number makes the equation true: $\Box + 0 = 10$?

   $10$. Adding 0 doesn't change the number.

2. What number makes the equation true: $14 = ? + 9$?

   $5$. Subtract $9$ from $14$ to find the first addend.

3. What number makes the equation true: $9 = ? - 1$?

   $10$. Add 1 to 9 to find the starting number.

4. What number makes the equation true: $\Box - 7 = 2$?

   $9$. Add 7 to 2 to find the starting number.

5. What number makes the equation true: $16 - 9 = \Box$?

   $7$. Subtract 9 from 16 to find the difference.

6. What number makes the equation true: $14 = \Box - 0$?

   $14$. Subtracting 0 doesn't change the number.

7. What number makes the equation true: $? - 5 = 7$?

   $12$. Add $5$ and $7$ to find the starting number.

8. What number makes the equation true: $6 + 6 = \Box$?

   $12$. Add 6 plus 6 to find the sum.

9. What number makes the equation true: $4 = 11 - \Box$?

   $7$. Subtract 4 from 11 to find what was taken away.

10. What number makes the equation true: $\Box = 6 + 2$?

    $8$. Add 6 plus 2 to find the sum.

11. What number makes the equation true: $15 - 8 = ?$?

    $7$. Subtract 8 from 15 to get 7.

12. What number makes the equation true: $0 + ? = 6$?

    $6$. Adding 0 doesn't change the result.

13. What number makes the equation true: $18 = 9 + ?$?

    $9$. Subtract 9 from 18 to find the missing addend.

14. What number makes the equation true: $9 - \Box = 0$?

    $9$. Subtracting a number from itself equals 0.

15. What number makes the equation true: $11 = 4 + ?$?

    $7$. Subtract 4 from 11 to find the missing addend.

16. What number makes the equation true: $\Box - 3 = 5$?

    $8$. Add 3 to 5 to find the starting number.

17. What number makes the equation true: $8 = 14 - ?$?

    $6$. Subtract $8$ from $14$ to find what was subtracted.

18. What number makes the equation true: $10 - \Box = 6$?

    $4$. Subtract 6 from 10 to find what was taken away.

19. What number makes the equation true: $\Box = 17 - 8$?

    $9$. Subtract 8 from 17 to find the difference.

20. What number makes the equation true: $6 + 6 = ?$?

    $12$. Add 6 plus 6 to get 12.

21. What number makes the equation true: $9 + ? = 15$?

    $6$. Subtract $9$ from $15$ to find what to add.

22. What number makes the equation true: $15 = 12 + \Box$?

    $3$. Subtract 12 from 15 to find the missing addend.

23. What number makes the equation true: $16 - 9 = ?$

    $7$. Subtract $9$ from $16$ to get the result.

24. What number makes the equation true: $\Box + 5 = 9$?

    $4$. Subtract 5 from 9 to find the missing addend.

25. What number makes the equation true: $16 - ? = 10$?

    $6$. Subtract 10 from 16 to find what was taken away.

26. What number makes the equation true: $11 - 3 = ?$?

    $8$. Subtract $3$ from $11$ to find the difference.

27. What number makes the equation true: $? + 7 = 12$?

    $5$. Subtract $7$ from $12$ to find the first number.

28. What number makes the equation true: $14 = ? + 5$?

    $9$. Subtract 5 from 14 to find the first addend.

29. What number makes the equation true: $7 + 8 = ?$?

    $15$. Add the two numbers to get the total.

30. What number makes the equation true: $12 - 5 = ?$?

    $7$. Subtract 5 from 12 to get 7.

31. What number makes the equation true: $9 + \Box = 14$?

    $5$. Count up from 9 to 14 to find the missing addend.

32. What number makes the equation true: $18 = \Box + 9$?

    $9$. Subtract 9 from 18 to find the missing addend.

33. What number makes the equation true: $10 = 6 + ?$?

    $4$. Subtract 6 from 10 to find the missing addend.

34. What number makes the equation true: $7 + ? = 7$?

    $0$. Adding 0 doesn't change the number.

35. What number makes the equation true: $13 - ? = 9$?

    $4$. Subtract 9 from 13 to find what was taken away.

36. What number makes the equation true: $4 = ? - 1$?

    $5$. Add $1$ and $4$ to find the first number.

37. What number makes the equation true: $? - 0 = 11$?

    $11$. Subtracting 0 doesn't change the number.

38. What number makes the equation true: $20 - 11 = \Box$?

    $9$. Subtract 11 from 20 to find the difference.

39. What number makes the equation true: $8 + ? = 11$?

    $3$. Add 3 to 8 to get 11.

40. What number makes the equation true: $? - 7 = 2$?

    $9$. Add 7 to 2 to find the starting number.

41. What number makes the equation true: $7 + \Box = 7$?

    $0$. Adding 0 to any number gives the same number.

42. What number makes the equation true: $? + 4 = 9$?

    $5$. Subtract 4 from 9 to find the missing number.

43. What number makes the equation true: $? + 3 = 12$?

    $9$. Subtract 3 from 12 to find the missing addend.

44. What number makes the equation true: $? - 8 = 6$?

    $14$. Add $8$ and $6$ to find the first number.

45. What number makes the equation true: $8 + \Box = 11$?

    $3$. Count up from 8 to 11 to find the missing addend.

46. What number makes the equation true: $? + 6 = 10$?

    $4$. Subtract $6$ from $10$ to find the missing number.

47. What number makes the equation true: $17 - 7 = ?$?

    $10$. Subtract $7$ from $17$ to find the difference.

48. What number makes the equation true: $? + 7 = 15$?

    $8$. Subtract 7 from 15 to find the missing addend.

49. What number makes the equation true: $5 = \Box - 3$?

    $8$. Add 3 to 5 to find the starting number.

50. What number makes the equation true: $13 - \Box = 13$?

    $0$. Subtracting 0 doesn't change the number.

51. What number makes the equation true: $20 - ? = 13$?

    $7$. Subtract 13 from 20 to find what was taken away.

52. What number makes the equation true: $13 = 5 + ?$?

    $8$. Subtract $5$ from $13$ to find the missing addend.

53. What number makes the equation true: $3 = 9 - ?$?

    $6$. Subtract $3$ from $9$ to find what was taken away.

54. What number makes the equation true: $5 = ? - 3$?

    $8$. Add $3$ and $5$ to find the starting number.

55. What number makes the equation true: $18 = ? - 2$?

    $20$. Add $2$ and $18$ to find the starting number.

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