← 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 677 · 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. 1.616 + 99 =
  2. 2.642 − 99 =
  3. 3.78 − 9 =
  4. 4.74 − 19 =
  5. 5.813 − 99 =
  6. 6.26 + 9 =
  7. 7.80 − 9 =
  8. 8.17 − 9 =
  9. 9.49 − 29 =
  10. 10.571 − 99 =
  11. 11.37 + 9 =
  12. 12.15 + 19 =
  13. 13.44 + 9 =
  14. 14.53 − 29 =
  15. 15.21 + 9 =
  16. 16.58 + 9 =
  17. 17.73 − 9 =
  18. 18.22 − 19 =
  19. 19.73 + 9 =
  20. 20.40 − 29 =
  21. 21.35 + 9 =
  22. 22.825 − 99 =
  23. 23.76 + 19 =
  24. 24.65 + 19 =
  25. 25.466 + 99 =
  26. 26.45 + 9 =
  27. 27.35 − 9 =
  28. 28.38 + 9 =
  29. 29.19 + 9 =
  30. 30.60 + 29 =
  31. 31.86 − 29 =
  32. 32.80 + 19 =
  33. 33.78 − 29 =
  34. 34.43 + 29 =
  35. 35.49 + 29 =
  36. 36.69 + 9 =
  37. 37.351 + 99 =
  38. 38.269 − 99 =
  39. 39.24 + 9 =
  40. 40.284 + 99 =

Answer key

  1. 715
  2. 543
  3. 69
  4. 55
  5. 714
  6. 35
  7. 71
  8. 8
  9. 20
  10. 472
  11. 46
  12. 34
  13. 53
  14. 24
  15. 30
  16. 67
  17. 64
  18. 3
  19. 82
  20. 11
  21. 44
  22. 726
  23. 95
  24. 84
  25. 565
  26. 54
  27. 26
  28. 47
  29. 28
  30. 89
  31. 57
  32. 99
  33. 49
  34. 72
  35. 78
  36. 78
  37. 450
  38. 170
  39. 33
  40. 383

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