Add and Subtract Within 100 - 2nd Grade Math

1. What is $29 + 35$?

   $64$. Add ones: $9+5=14$, carry 1; add tens: $2+3+1=6$.

2. What is $38 + 24$?

   $62$. Add ones: $8+4=12$, carry 1; add tens: $3+2+1=6$.

3. What is $71 - 27$?

   $44$. Regroup: $71-27 = 61+10-27 = 44$.

4. What is $90 - 46$?

   $44$. Subtract: $90-46 = 90-40-6 = 50-6 = 44$.

5. What is $71 - 9$?

   $62$. Count back $9$ from $71$: $71 - 9 = 62$.

6. What is $100 - 63$?

   $37$. Subtract: $100-63 = 100-60-3 = 40-3 = 37$.

7. What is $50 + 27$?

   $77$. Add tens: $50 + 20 = 70$, then add ones: $7$.

8. What number makes the equation true: $63 - \Box = 40$?

   $23$. Find what was subtracted: $63 - 40 = 23$.

9. Identify the related subtraction fact for $9 + 34 = 43$.

   $43 - 34 = 9$. Addition and subtraction are inverse operations.

10. What is $74 - 18$?

    $56$. Subtract ones first: $74 - 8 = 66$, then subtract ten: $66 - 10 = 56$.

11. What is $36 + 28$?

    $64$. Add ones: $6+8=14$, carry 1; add tens: $3+2+1=6$.

12. What is $46 + 19$?

    $65$. Break apart $19$: $46 + 19 = 46 + 4 + 15 = 50 + 15 = 65$.

13. What is $47 + 30$?

    $77$. Add the tens first: $40 + 30 = 70$, then add the ones: $7$.

14. What is $36 + 40$?

    $76$. Add tens: $30 + 40 = 70$, then add ones: $6$.

15. What is $95 - 50$?

    $45$. Subtract tens: $90 - 50 = 40$, then add ones: $5$.

16. What number makes the equation true: $\Box + 28 = 70$?

    $42$. Find the missing addend: $70 - 28 = 42$.

17. What is $58 + 7$?

    $65$. Add ones: $8+7=15$, carry 1; add tens: $5+1=6$.

18. What is $29 + 8$?

    $37$. Make a ten: $29 + 1 = 30$, then $30 + 7 = 37$.

19. What is $38 + 7$?

    $45$. Add ones to get $45$: $38 + 7 = 38 + 2 + 5 = 40 + 5$.

20. What is $39 + 26$?

    $65$. Make a ten: $39 + 1 = 40$, then $40 + 25 = 65$.

21. What is $64 - 8$?

    $56$. Subtract ones: $4-8$ needs regrouping; $14-8=6$, $5-0=5$.

22. What is $27 + 48$?

    $75$. Add ones: $7+8=15$, carry 1; add tens: $2+4+1=7$.

23. What is $58 + 24$?

    $82$. Add tens: $50 + 20 = 70$, then add ones: $8 + 4 = 12$, so $70 + 12 = 82$.

24. What is $34 + 9$?

    $43$. Add ones: $4+9=13$, carry 1; add tens: $3+1=4$.

25. What is $68 - 39$?

    $29$. Regroup: $68-39 = 58+10-39 = 29$.

26. What is $49 + 16$?

    $65$. Add ones: $9+6=15$, carry 1; add tens: $4+1+1=6$.

27. What is $62 - 20$?

    $42$. Subtract the tens: $60 - 20 = 40$, then add the ones: $2$.

28. What is $92 - 48$?

    $44$. Regroup: $92-48 = 82+10-48 = 44$.

29. What is $56 + 18$?

    $74$. Add ones: $6+8=14$, carry 1; add tens: $5+1+1=7$.

30. What is $47 + 25$?

    $72$. Add ones: $7+5=12$, carry 1; add tens: $4+2+1=7$.

31. What is $67 - 28$?

    $39$. Subtract tens: $67 - 20 = 47$, then subtract ones: $47 - 8 = 39$.

32. What is $54 - 6$?

    $48$. Count back $6$ from $54$: $54 - 6 = 48$.

33. What is $61 - 35$?

    $26$. Regroup: $61-35 = 51+10-35 = 26$.

34. What is $83 - 27$?

    $56$. Subtract tens then ones: $83 - 20 = 63$, then $63 - 7 = 56$.

35. What is $45 + 19$?

    $64$. Add ones: $5+9=14$, carry 1; add tens: $4+1+1=6$.

36. What is $70 - 28$?

    $42$. Subtract: $70-28 = 70-20-8 = 50-8 = 42$.

37. What is $52 - 6$?

    $46$. Subtract ones: $2-6$ needs regrouping; $12-6=6$, $4-0=4$.

38. What is $48 + 25$?

    $73$. Add tens: $40 + 20 = 60$, then add ones: $8 + 5 = 13$, so $60 + 13 = 73$.

39. What is $90 - 35$?

    $55$. Subtract tens: $90 - 30 = 60$, then subtract ones: $60 - 5 = 55$.

40. What is $83 - 57$?

    $26$. Regroup: $83-57 = 73+10-57 = 26$.

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