← 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 67 · 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. 1.146 + 99 =
  2. 2.80 − 9 =
  3. 3.53 + 9 =
  4. 4.424 − 99 =
  5. 5.88 − 29 =
  6. 6.59 + 29 =
  7. 7.26 − 9 =
  8. 8.41 − 9 =
  9. 9.55 + 9 =
  10. 10.76 − 29 =
  11. 11.65 − 19 =
  12. 12.85 − 19 =
  13. 13.55 − 29 =
  14. 14.781 − 99 =
  15. 15.220 + 99 =
  16. 16.89 − 9 =
  17. 17.44 + 9 =
  18. 18.62 + 9 =
  19. 19.41 + 9 =
  20. 20.185 − 99 =
  21. 21.21 + 29 =
  22. 22.73 + 9 =
  23. 23.66 + 29 =
  24. 24.688 − 99 =
  25. 25.60 + 9 =
  26. 26.15 + 29 =
  27. 27.44 + 29 =
  28. 28.15 + 19 =
  29. 29.253 − 99 =
  30. 30.597 + 99 =
  31. 31.71 − 9 =
  32. 32.46 − 9 =
  33. 33.78 − 9 =
  34. 34.49 − 9 =
  35. 35.28 + 29 =
  36. 36.307 − 99 =
  37. 37.72 + 9 =
  38. 38.764 − 99 =
  39. 39.274 + 99 =
  40. 40.536 + 99 =

Answer key

  1. 245
  2. 71
  3. 62
  4. 325
  5. 59
  6. 88
  7. 17
  8. 32
  9. 64
  10. 47
  11. 46
  12. 66
  13. 26
  14. 682
  15. 319
  16. 80
  17. 53
  18. 71
  19. 50
  20. 86
  21. 50
  22. 82
  23. 95
  24. 589
  25. 69
  26. 44
  27. 73
  28. 34
  29. 154
  30. 696
  31. 62
  32. 37
  33. 69
  34. 40
  35. 57
  36. 208
  37. 81
  38. 665
  39. 373
  40. 635

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