← 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 76 · 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. 1.95 − 19 =
  2. 2.109 − 29 =
  3. 3.563 + 99 =
  4. 4.93 − 19 =
  5. 5.784 + 99 =
  6. 6.56 − 19 =
  7. 7.686 + 99 =
  8. 8.47 + 29 =
  9. 9.70 − 9 =
  10. 10.78 + 19 =
  11. 11.64 − 29 =
  12. 12.809 − 99 =
  13. 13.21 + 9 =
  14. 14.66 + 29 =
  15. 15.26 + 29 =
  16. 16.40 − 29 =
  17. 17.51 − 19 =
  18. 18.623 + 99 =
  19. 19.68 − 9 =
  20. 20.745 − 99 =
  21. 21.310 − 99 =
  22. 22.32 + 29 =
  23. 23.42 + 9 =
  24. 24.75 + 29 =
  25. 25.73 − 29 =
  26. 26.204 − 99 =
  27. 27.57 − 19 =
  28. 28.105 − 29 =
  29. 29.62 + 29 =
  30. 30.772 − 99 =
  31. 31.78 + 29 =
  32. 32.84 − 19 =
  33. 33.609 + 99 =
  34. 34.12 + 9 =
  35. 35.792 + 99 =
  36. 36.224 + 99 =
  37. 37.31 + 19 =
  38. 38.286 + 99 =
  39. 39.65 + 9 =
  40. 40.481 − 99 =

Answer key

  1. 76
  2. 80
  3. 662
  4. 74
  5. 883
  6. 37
  7. 785
  8. 76
  9. 61
  10. 97
  11. 35
  12. 710
  13. 30
  14. 95
  15. 55
  16. 11
  17. 32
  18. 722
  19. 59
  20. 646
  21. 211
  22. 61
  23. 51
  24. 104
  25. 44
  26. 105
  27. 38
  28. 76
  29. 91
  30. 673
  31. 107
  32. 65
  33. 708
  34. 21
  35. 891
  36. 323
  37. 50
  38. 385
  39. 74
  40. 382

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