← 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 18 · 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. 1.27 + 9 =
  2. 2.407 + 99 =
  3. 3.69 − 19 =
  4. 4.72 + 9 =
  5. 5.802 − 99 =
  6. 6.65 + 19 =
  7. 7.40 + 19 =
  8. 8.256 + 99 =
  9. 9.757 + 99 =
  10. 10.403 + 99 =
  11. 11.28 + 9 =
  12. 12.65 − 9 =
  13. 13.38 + 29 =
  14. 14.58 − 9 =
  15. 15.485 + 99 =
  16. 16.54 + 29 =
  17. 17.70 + 29 =
  18. 18.34 + 19 =
  19. 19.758 − 99 =
  20. 20.26 + 19 =
  21. 21.25 + 9 =
  22. 22.418 + 99 =
  23. 23.63 − 9 =
  24. 24.34 − 9 =
  25. 25.60 − 29 =
  26. 26.582 − 99 =
  27. 27.698 − 99 =
  28. 28.22 + 9 =
  29. 29.13 + 9 =
  30. 30.20 + 29 =
  31. 31.26 + 9 =
  32. 32.447 − 99 =
  33. 33.30 + 19 =
  34. 34.79 + 19 =
  35. 35.81 − 29 =
  36. 36.60 − 9 =
  37. 37.54 − 19 =
  38. 38.522 + 99 =
  39. 39.69 − 9 =
  40. 40.65 − 19 =

Answer key

  1. 36
  2. 506
  3. 50
  4. 81
  5. 703
  6. 84
  7. 59
  8. 355
  9. 856
  10. 502
  11. 37
  12. 56
  13. 67
  14. 49
  15. 584
  16. 83
  17. 99
  18. 53
  19. 659
  20. 45
  21. 34
  22. 517
  23. 54
  24. 25
  25. 31
  26. 483
  27. 599
  28. 31
  29. 22
  30. 49
  31. 35
  32. 348
  33. 49
  34. 98
  35. 52
  36. 51
  37. 35
  38. 621
  39. 60
  40. 46

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