← 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 745 · 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. 1.35 − 19 =
  2. 2.21 + 9 =
  3. 3.179 + 99 =
  4. 4.786 − 99 =
  5. 5.54 − 9 =
  6. 6.81 − 9 =
  7. 7.327 − 99 =
  8. 8.18 + 19 =
  9. 9.25 − 9 =
  10. 10.565 + 99 =
  11. 11.44 − 9 =
  12. 12.65 + 9 =
  13. 13.69 + 19 =
  14. 14.70 + 9 =
  15. 15.58 + 9 =
  16. 16.277 − 99 =
  17. 17.68 − 9 =
  18. 18.318 + 99 =
  19. 19.26 + 9 =
  20. 20.17 + 19 =
  21. 21.41 + 9 =
  22. 22.39 − 29 =
  23. 23.51 + 9 =
  24. 24.14 + 9 =
  25. 25.39 + 19 =
  26. 26.32 − 29 =
  27. 27.34 − 29 =
  28. 28.75 + 9 =
  29. 29.39 − 9 =
  30. 30.65 − 9 =
  31. 31.55 + 9 =
  32. 32.332 − 99 =
  33. 33.89 − 9 =
  34. 34.64 − 19 =
  35. 35.422 − 99 =
  36. 36.25 + 29 =
  37. 37.309 − 99 =
  38. 38.52 + 19 =
  39. 39.41 + 19 =
  40. 40.94 − 29 =

Answer key

  1. 16
  2. 30
  3. 278
  4. 687
  5. 45
  6. 72
  7. 228
  8. 37
  9. 16
  10. 664
  11. 35
  12. 74
  13. 88
  14. 79
  15. 67
  16. 178
  17. 59
  18. 417
  19. 35
  20. 36
  21. 50
  22. 10
  23. 60
  24. 23
  25. 58
  26. 3
  27. 5
  28. 84
  29. 30
  30. 56
  31. 64
  32. 233
  33. 80
  34. 45
  35. 323
  36. 54
  37. 210
  38. 71
  39. 60
  40. 65

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