← 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 371 · 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. 1.24 − 9 =
  2. 2.40 − 9 =
  3. 3.20 + 29 =
  4. 4.100 − 29 =
  5. 5.33 − 29 =
  6. 6.52 − 9 =
  7. 7.44 + 9 =
  8. 8.28 − 19 =
  9. 9.60 − 19 =
  10. 10.535 + 99 =
  11. 11.15 + 9 =
  12. 12.69 + 29 =
  13. 13.69 + 19 =
  14. 14.395 + 99 =
  15. 15.761 + 99 =
  16. 16.418 + 99 =
  17. 17.50 − 9 =
  18. 18.12 + 29 =
  19. 19.17 + 19 =
  20. 20.87 − 19 =
  21. 21.47 + 9 =
  22. 22.48 + 9 =
  23. 23.51 − 19 =
  24. 24.32 − 19 =
  25. 25.50 + 9 =
  26. 26.219 + 99 =
  27. 27.22 − 9 =
  28. 28.624 + 99 =
  29. 29.46 + 19 =
  30. 30.78 − 9 =
  31. 31.45 − 19 =
  32. 32.571 + 99 =
  33. 33.737 + 99 =
  34. 34.47 − 9 =
  35. 35.55 − 19 =
  36. 36.87 − 29 =
  37. 37.865 − 99 =
  38. 38.858 − 99 =
  39. 39.709 + 99 =
  40. 40.49 − 29 =

Answer key

  1. 15
  2. 31
  3. 49
  4. 71
  5. 4
  6. 43
  7. 53
  8. 9
  9. 41
  10. 634
  11. 24
  12. 98
  13. 88
  14. 494
  15. 860
  16. 517
  17. 41
  18. 41
  19. 36
  20. 68
  21. 56
  22. 57
  23. 32
  24. 13
  25. 59
  26. 318
  27. 13
  28. 723
  29. 65
  30. 69
  31. 26
  32. 670
  33. 836
  34. 38
  35. 36
  36. 58
  37. 766
  38. 759
  39. 808
  40. 20

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