Addition within 20 worksheets

  • Level: Grade 1 – Grade 2
  • Free
  • Printable
  • Answer key included

Sums to 20 cover every single-digit addition fact a student needs. Fluency here is a key goal of first and second grade in most curricula, including the US Common Core (1.OA.C.6 and 2.OA.B.2).

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Addition within 20 worksheets
Name: Date: Score: / 40

Add the numbers.

  1. 1.
    18 + 2 =
  2. 2.
    8 + 2 =
  3. 3.
    17 + 3 =
  4. 4.
    16 + 2 =
  5. 5.
    13 + 1 =
  6. 6.
    17 + 1 =
  7. 7.
    13 + 5 =
  8. 8.
    12 + 8 =
  9. 9.
    5 + 8 =
  10. 10.
    20 + 0 =
  11. 11.
    19 + 0 =
  12. 12.
    12 + 3 =
  13. 13.
    9 + 6 =
  14. 14.
    16 + 1 =
  15. 15.
    1 + 7 =
  16. 16.
    8 + 9 =
  17. 17.
    6 + 3 =
  18. 18.
    5 + 14 =
  19. 19.
    17 + 0 =
  20. 20.
    5 + 6 =
  21. 21.
    14 + 3 =
  22. 22.
    3 + 14 =
  23. 23.
    13 + 6 =
  24. 24.
    10 + 8 =
  25. 25.
    7 + 5 =
  26. 26.
    1 + 12 =
  27. 27.
    14 + 6 =
  28. 28.
    0 + 6 =
  29. 29.
    0 + 8 =
  30. 30.
    3 + 9 =
  31. 31.
    6 + 11 =
  32. 32.
    13 + 2 =
  33. 33.
    15 + 5 =
  34. 34.
    10 + 9 =
  35. 35.
    18 + 1 =
  36. 36.
    11 + 4 =
  37. 37.
    18 + 0 =
  38. 38.
    17 + 2 =
  39. 39.
    12 + 6 =
  40. 40.
    7 + 12 =
MathSheetLabWorksheet #293504
Addition within 20 worksheets Answer key
  1. 1.
    18 + 2 = 20
  2. 2.
    8 + 2 = 10
  3. 3.
    17 + 3 = 20
  4. 4.
    16 + 2 = 18
  5. 5.
    13 + 1 = 14
  6. 6.
    17 + 1 = 18
  7. 7.
    13 + 5 = 18
  8. 8.
    12 + 8 = 20
  9. 9.
    5 + 8 = 13
  10. 10.
    20 + 0 = 20
  11. 11.
    19 + 0 = 19
  12. 12.
    12 + 3 = 15
  13. 13.
    9 + 6 = 15
  14. 14.
    16 + 1 = 17
  15. 15.
    1 + 7 = 8
  16. 16.
    8 + 9 = 17
  17. 17.
    6 + 3 = 9
  18. 18.
    5 + 14 = 19
  19. 19.
    17 + 0 = 17
  20. 20.
    5 + 6 = 11
  21. 21.
    14 + 3 = 17
  22. 22.
    3 + 14 = 17
  23. 23.
    13 + 6 = 19
  24. 24.
    10 + 8 = 18
  25. 25.
    7 + 5 = 12
  26. 26.
    1 + 12 = 13
  27. 27.
    14 + 6 = 20
  28. 28.
    0 + 6 = 6
  29. 29.
    0 + 8 = 8
  30. 30.
    3 + 9 = 12
  31. 31.
    6 + 11 = 17
  32. 32.
    13 + 2 = 15
  33. 33.
    15 + 5 = 20
  34. 34.
    10 + 9 = 19
  35. 35.
    18 + 1 = 19
  36. 36.
    11 + 4 = 15
  37. 37.
    18 + 0 = 18
  38. 38.
    17 + 2 = 19
  39. 39.
    12 + 6 = 18
  40. 40.
    7 + 12 = 19
MathSheetLabWorksheet #293504

About this worksheet

Problems are written horizontally to encourage mental strategies such as "make ten" (8 + 5 = 8 + 2 + 3) instead of column procedures.

Each sheet contains 20, 30, 40 or 50 problems (your choice) and is generated at random. Press “New problems” as many times as you like; there is no limit and no account needed.

Worked example

18 + 0 =
  1. Start at the larger number, 18.
  2. Adding 0 changes nothing.
  3. 18 + 0 = 18.

Answer: 18

Teaching tips

  • Teach "make ten" and "doubles plus one" strategies explicitly.
  • Mix in a few facts the student finds hard and repeat the sheet with the same link a week later.

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