← 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 516 · 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. 1.76 + 9 =
  2. 2.867 − 99 =
  3. 3.66 + 19 =
  4. 4.372 − 99 =
  5. 5.66 + 9 =
  6. 6.54 + 19 =
  7. 7.57 + 9 =
  8. 8.48 − 9 =
  9. 9.22 + 9 =
  10. 10.130 + 99 =
  11. 11.63 + 9 =
  12. 12.78 + 29 =
  13. 13.36 + 29 =
  14. 14.496 + 99 =
  15. 15.81 − 9 =
  16. 16.284 + 99 =
  17. 17.729 + 99 =
  18. 18.66 − 19 =
  19. 19.44 + 29 =
  20. 20.181 + 99 =
  21. 21.46 + 29 =
  22. 22.13 + 9 =
  23. 23.72 + 29 =
  24. 24.79 − 29 =
  25. 25.736 + 99 =
  26. 26.43 − 19 =
  27. 27.29 + 9 =
  28. 28.191 − 99 =
  29. 29.30 + 9 =
  30. 30.53 − 9 =
  31. 31.16 + 9 =
  32. 32.485 + 99 =
  33. 33.27 − 9 =
  34. 34.54 + 29 =
  35. 35.643 + 99 =
  36. 36.64 + 29 =
  37. 37.62 + 19 =
  38. 38.90 − 19 =
  39. 39.47 + 29 =
  40. 40.12 − 9 =

Answer key

  1. 85
  2. 768
  3. 85
  4. 273
  5. 75
  6. 73
  7. 66
  8. 39
  9. 31
  10. 229
  11. 72
  12. 107
  13. 65
  14. 595
  15. 72
  16. 383
  17. 828
  18. 47
  19. 73
  20. 280
  21. 75
  22. 22
  23. 101
  24. 50
  25. 835
  26. 24
  27. 38
  28. 92
  29. 39
  30. 44
  31. 25
  32. 584
  33. 18
  34. 83
  35. 742
  36. 93
  37. 81
  38. 71
  39. 76
  40. 3

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