← 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 577 · 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. 1.97 − 19 =
  2. 2.115 + 99 =
  3. 3.341 − 99 =
  4. 4.194 − 99 =
  5. 5.58 − 19 =
  6. 6.163 + 99 =
  7. 7.560 + 99 =
  8. 8.24 − 19 =
  9. 9.41 − 9 =
  10. 10.86 − 29 =
  11. 11.54 − 19 =
  12. 12.82 − 9 =
  13. 13.13 + 29 =
  14. 14.32 + 29 =
  15. 15.72 − 29 =
  16. 16.75 + 19 =
  17. 17.366 − 99 =
  18. 18.28 − 9 =
  19. 19.55 − 29 =
  20. 20.796 − 99 =
  21. 21.240 + 99 =
  22. 22.30 + 29 =
  23. 23.353 + 99 =
  24. 24.29 − 9 =
  25. 25.36 − 29 =
  26. 26.313 + 99 =
  27. 27.75 + 29 =
  28. 28.24 + 19 =
  29. 29.31 − 9 =
  30. 30.20 + 19 =
  31. 31.80 − 19 =
  32. 32.18 − 9 =
  33. 33.717 + 99 =
  34. 34.25 + 29 =
  35. 35.776 + 99 =
  36. 36.654 + 99 =
  37. 37.613 + 99 =
  38. 38.46 − 9 =
  39. 39.73 + 19 =
  40. 40.324 − 99 =

Answer key

  1. 78
  2. 214
  3. 242
  4. 95
  5. 39
  6. 262
  7. 659
  8. 5
  9. 32
  10. 57
  11. 35
  12. 73
  13. 42
  14. 61
  15. 43
  16. 94
  17. 267
  18. 19
  19. 26
  20. 697
  21. 339
  22. 59
  23. 452
  24. 20
  25. 7
  26. 412
  27. 104
  28. 43
  29. 22
  30. 39
  31. 61
  32. 9
  33. 816
  34. 54
  35. 875
  36. 753
  37. 712
  38. 37
  39. 92
  40. 225

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