← 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 75 · 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. 1.836 − 99 =
  2. 2.534 − 99 =
  3. 3.73 + 29 =
  4. 4.91 − 29 =
  5. 5.36 + 9 =
  6. 6.736 + 99 =
  7. 7.12 + 19 =
  8. 8.693 + 99 =
  9. 9.44 + 9 =
  10. 10.54 − 29 =
  11. 11.434 + 99 =
  12. 12.599 − 99 =
  13. 13.61 + 29 =
  14. 14.49 + 9 =
  15. 15.511 − 99 =
  16. 16.392 − 99 =
  17. 17.167 − 99 =
  18. 18.17 − 9 =
  19. 19.84 − 9 =
  20. 20.94 − 19 =
  21. 21.30 + 19 =
  22. 22.46 + 19 =
  23. 23.72 + 9 =
  24. 24.57 − 29 =
  25. 25.12 + 9 =
  26. 26.33 − 9 =
  27. 27.672 + 99 =
  28. 28.29 + 29 =
  29. 29.93 − 29 =
  30. 30.51 + 9 =
  31. 31.67 − 29 =
  32. 32.62 − 9 =
  33. 33.27 + 19 =
  34. 34.45 + 9 =
  35. 35.25 − 9 =
  36. 36.32 − 9 =
  37. 37.31 + 9 =
  38. 38.77 + 9 =
  39. 39.40 + 19 =
  40. 40.99 − 19 =

Answer key

  1. 737
  2. 435
  3. 102
  4. 62
  5. 45
  6. 835
  7. 31
  8. 792
  9. 53
  10. 25
  11. 533
  12. 500
  13. 90
  14. 58
  15. 412
  16. 293
  17. 68
  18. 8
  19. 75
  20. 75
  21. 49
  22. 65
  23. 81
  24. 28
  25. 21
  26. 24
  27. 771
  28. 58
  29. 64
  30. 60
  31. 38
  32. 53
  33. 46
  34. 54
  35. 16
  36. 23
  37. 40
  38. 86
  39. 59
  40. 80

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