← 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 894 · 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. 1.57 − 29 =
  2. 2.36 − 19 =
  3. 3.78 + 19 =
  4. 4.33 − 19 =
  5. 5.72 + 9 =
  6. 6.765 + 99 =
  7. 7.65 + 9 =
  8. 8.562 + 99 =
  9. 9.13 − 9 =
  10. 10.650 − 99 =
  11. 11.71 + 29 =
  12. 12.60 − 19 =
  13. 13.81 − 19 =
  14. 14.70 + 29 =
  15. 15.229 − 99 =
  16. 16.24 + 9 =
  17. 17.89 − 19 =
  18. 18.73 + 9 =
  19. 19.26 − 19 =
  20. 20.357 − 99 =
  21. 21.32 + 29 =
  22. 22.61 + 19 =
  23. 23.213 − 99 =
  24. 24.43 − 29 =
  25. 25.13 + 19 =
  26. 26.89 − 9 =
  27. 27.19 + 19 =
  28. 28.68 − 29 =
  29. 29.762 − 99 =
  30. 30.101 − 29 =
  31. 31.687 + 99 =
  32. 32.31 + 9 =
  33. 33.37 − 9 =
  34. 34.18 − 9 =
  35. 35.66 + 29 =
  36. 36.75 + 29 =
  37. 37.38 − 29 =
  38. 38.35 − 19 =
  39. 39.64 − 29 =
  40. 40.22 − 9 =

Answer key

  1. 28
  2. 17
  3. 97
  4. 14
  5. 81
  6. 864
  7. 74
  8. 661
  9. 4
  10. 551
  11. 100
  12. 41
  13. 62
  14. 99
  15. 130
  16. 33
  17. 70
  18. 82
  19. 7
  20. 258
  21. 61
  22. 80
  23. 114
  24. 14
  25. 32
  26. 80
  27. 38
  28. 39
  29. 663
  30. 72
  31. 786
  32. 40
  33. 28
  34. 9
  35. 95
  36. 104
  37. 9
  38. 16
  39. 35
  40. 13

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