← Add and take away 9, 19 and 99 lesson New set →

Adding 9, 19 and 99 Mental Maths Worksheet

Mental maths lesson 4: Add and take away 9, 19 and 99 · Set 623 · 40 questions
TalentJR

How to do it in your head (Round and adjust): Add 9, 19, 99: add 10, 20, 100, then take 1 away. Take away 9, 19, 99: take away 10, 20, 100, then add 1 back. Ask yourself: did I use too much or too little?

NameDateTime takenScore ___ / 40
  1. 1.72 + 19 =
  2. 2.42 − 29 =
  3. 3.81 − 29 =
  4. 4.74 + 19 =
  5. 5.167 − 99 =
  6. 6.13 + 19 =
  7. 7.107 − 29 =
  8. 8.709 − 99 =
  9. 9.49 − 9 =
  10. 10.43 + 9 =
  11. 11.32 + 29 =
  12. 12.19 + 19 =
  13. 13.46 + 19 =
  14. 14.21 + 9 =
  15. 15.58 − 29 =
  16. 16.38 + 29 =
  17. 17.18 + 29 =
  18. 18.43 − 19 =
  19. 19.46 − 9 =
  20. 20.24 + 19 =
  21. 21.32 − 9 =
  22. 22.25 + 19 =
  23. 23.35 + 9 =
  24. 24.34 + 9 =
  25. 25.70 − 29 =
  26. 26.565 − 99 =
  27. 27.450 + 99 =
  28. 28.687 + 99 =
  29. 29.340 + 99 =
  30. 30.57 − 29 =
  31. 31.22 − 19 =
  32. 32.90 − 19 =
  33. 33.46 + 9 =
  34. 34.738 − 99 =
  35. 35.43 − 29 =
  36. 36.231 + 99 =
  37. 37.486 − 99 =
  38. 38.83 − 19 =
  39. 39.55 − 19 =
  40. 40.27 − 19 =

Answer key

  1. 91
  2. 13
  3. 52
  4. 93
  5. 68
  6. 32
  7. 78
  8. 610
  9. 40
  10. 52
  11. 61
  12. 38
  13. 65
  14. 30
  15. 29
  16. 67
  17. 47
  18. 24
  19. 37
  20. 43
  21. 23
  22. 44
  23. 44
  24. 43
  25. 41
  26. 466
  27. 549
  28. 786
  29. 439
  30. 28
  31. 3
  32. 71
  33. 55
  34. 639
  35. 14
  36. 330
  37. 387
  38. 64
  39. 36
  40. 8

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths