← 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 609 · 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. 1.58 − 29 =
  2. 2.78 + 29 =
  3. 3.48 − 9 =
  4. 4.38 + 29 =
  5. 5.78 + 19 =
  6. 6.75 + 19 =
  7. 7.55 + 9 =
  8. 8.88 − 9 =
  9. 9.57 − 19 =
  10. 10.58 − 9 =
  11. 11.297 − 99 =
  12. 12.68 + 29 =
  13. 13.32 + 29 =
  14. 14.480 − 99 =
  15. 15.76 − 9 =
  16. 16.80 + 29 =
  17. 17.28 − 9 =
  18. 18.13 − 9 =
  19. 19.21 + 19 =
  20. 20.67 + 29 =
  21. 21.23 − 19 =
  22. 22.70 − 29 =
  23. 23.59 + 19 =
  24. 24.45 − 19 =
  25. 25.862 − 99 =
  26. 26.78 − 19 =
  27. 27.529 + 99 =
  28. 28.574 + 99 =
  29. 29.38 − 19 =
  30. 30.79 + 29 =
  31. 31.38 + 9 =
  32. 32.200 + 99 =
  33. 33.12 + 19 =
  34. 34.389 − 99 =
  35. 35.29 − 19 =
  36. 36.49 + 19 =
  37. 37.72 − 9 =
  38. 38.44 − 9 =
  39. 39.67 − 9 =
  40. 40.41 + 9 =

Answer key

  1. 29
  2. 107
  3. 39
  4. 67
  5. 97
  6. 94
  7. 64
  8. 79
  9. 38
  10. 49
  11. 198
  12. 97
  13. 61
  14. 381
  15. 67
  16. 109
  17. 19
  18. 4
  19. 40
  20. 96
  21. 4
  22. 41
  23. 78
  24. 26
  25. 763
  26. 59
  27. 628
  28. 673
  29. 19
  30. 108
  31. 47
  32. 299
  33. 31
  34. 290
  35. 10
  36. 68
  37. 63
  38. 35
  39. 58
  40. 50

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