← 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 977 · 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. 1.62 − 9 =
  2. 2.48 + 19 =
  3. 3.365 + 99 =
  4. 4.32 + 29 =
  5. 5.40 − 19 =
  6. 6.76 − 19 =
  7. 7.231 − 99 =
  8. 8.703 + 99 =
  9. 9.14 + 29 =
  10. 10.285 + 99 =
  11. 11.882 − 99 =
  12. 12.39 − 29 =
  13. 13.76 + 19 =
  14. 14.69 + 29 =
  15. 15.19 + 19 =
  16. 16.96 − 19 =
  17. 17.23 + 29 =
  18. 18.53 + 19 =
  19. 19.44 − 9 =
  20. 20.496 + 99 =
  21. 21.14 − 9 =
  22. 22.82 − 9 =
  23. 23.670 − 99 =
  24. 24.61 + 29 =
  25. 25.65 + 19 =
  26. 26.29 − 9 =
  27. 27.66 − 9 =
  28. 28.663 + 99 =
  29. 29.21 − 9 =
  30. 30.82 − 29 =
  31. 31.30 − 9 =
  32. 32.13 + 29 =
  33. 33.343 − 99 =
  34. 34.46 + 9 =
  35. 35.374 + 99 =
  36. 36.156 + 99 =
  37. 37.61 + 19 =
  38. 38.333 + 99 =
  39. 39.91 − 19 =
  40. 40.79 − 29 =

Answer key

  1. 53
  2. 67
  3. 464
  4. 61
  5. 21
  6. 57
  7. 132
  8. 802
  9. 43
  10. 384
  11. 783
  12. 10
  13. 95
  14. 98
  15. 38
  16. 77
  17. 52
  18. 72
  19. 35
  20. 595
  21. 5
  22. 73
  23. 571
  24. 90
  25. 84
  26. 20
  27. 57
  28. 762
  29. 12
  30. 53
  31. 21
  32. 42
  33. 244
  34. 55
  35. 473
  36. 255
  37. 80
  38. 432
  39. 72
  40. 50

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