← 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 490 · 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. 1.21 + 9 =
  2. 2.25 + 9 =
  3. 3.85 − 29 =
  4. 4.85 − 19 =
  5. 5.30 + 9 =
  6. 6.40 − 19 =
  7. 7.20 − 9 =
  8. 8.55 − 29 =
  9. 9.28 − 9 =
  10. 10.17 + 19 =
  11. 11.27 − 19 =
  12. 12.16 + 19 =
  13. 13.26 + 9 =
  14. 14.891 − 99 =
  15. 15.73 − 29 =
  16. 16.31 + 9 =
  17. 17.49 − 29 =
  18. 18.35 − 9 =
  19. 19.77 − 19 =
  20. 20.49 − 9 =
  21. 21.55 + 9 =
  22. 22.12 + 19 =
  23. 23.24 − 9 =
  24. 24.93 − 29 =
  25. 25.47 − 9 =
  26. 26.19 − 9 =
  27. 27.59 − 9 =
  28. 28.523 + 99 =
  29. 29.609 + 99 =
  30. 30.220 + 99 =
  31. 31.479 − 99 =
  32. 32.14 + 9 =
  33. 33.66 + 19 =
  34. 34.63 + 19 =
  35. 35.62 + 19 =
  36. 36.666 + 99 =
  37. 37.65 + 9 =
  38. 38.63 − 19 =
  39. 39.61 + 9 =
  40. 40.361 + 99 =

Answer key

  1. 30
  2. 34
  3. 56
  4. 66
  5. 39
  6. 21
  7. 11
  8. 26
  9. 19
  10. 36
  11. 8
  12. 35
  13. 35
  14. 792
  15. 44
  16. 40
  17. 20
  18. 26
  19. 58
  20. 40
  21. 64
  22. 31
  23. 15
  24. 64
  25. 38
  26. 10
  27. 50
  28. 622
  29. 708
  30. 319
  31. 380
  32. 23
  33. 85
  34. 82
  35. 81
  36. 765
  37. 74
  38. 44
  39. 70
  40. 460

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