← 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 359 · 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. 1.30 + 9 =
  2. 2.51 − 19 =
  3. 3.39 + 19 =
  4. 4.26 + 19 =
  5. 5.169 + 99 =
  6. 6.49 − 9 =
  7. 7.81 − 19 =
  8. 8.63 − 29 =
  9. 9.40 − 29 =
  10. 10.14 − 9 =
  11. 11.27 − 19 =
  12. 12.79 + 29 =
  13. 13.32 + 29 =
  14. 14.75 − 29 =
  15. 15.70 − 29 =
  16. 16.51 + 9 =
  17. 17.733 + 99 =
  18. 18.43 − 29 =
  19. 19.62 + 29 =
  20. 20.30 − 19 =
  21. 21.345 + 99 =
  22. 22.85 − 19 =
  23. 23.502 + 99 =
  24. 24.74 + 19 =
  25. 25.64 + 19 =
  26. 26.47 + 9 =
  27. 27.76 − 29 =
  28. 28.695 − 99 =
  29. 29.366 − 99 =
  30. 30.405 + 99 =
  31. 31.722 − 99 =
  32. 32.77 + 9 =
  33. 33.61 + 19 =
  34. 34.55 − 29 =
  35. 35.43 + 19 =
  36. 36.77 + 29 =
  37. 37.12 − 9 =
  38. 38.582 − 99 =
  39. 39.80 − 9 =
  40. 40.284 + 99 =

Answer key

  1. 39
  2. 32
  3. 58
  4. 45
  5. 268
  6. 40
  7. 62
  8. 34
  9. 11
  10. 5
  11. 8
  12. 108
  13. 61
  14. 46
  15. 41
  16. 60
  17. 832
  18. 14
  19. 91
  20. 11
  21. 444
  22. 66
  23. 601
  24. 93
  25. 83
  26. 56
  27. 47
  28. 596
  29. 267
  30. 504
  31. 623
  32. 86
  33. 80
  34. 26
  35. 62
  36. 106
  37. 3
  38. 483
  39. 71
  40. 383

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