← 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 196 · 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. 1.31 + 9 =
  2. 2.74 + 19 =
  3. 3.334 − 99 =
  4. 4.63 − 29 =
  5. 5.62 − 9 =
  6. 6.49 + 29 =
  7. 7.19 + 19 =
  8. 8.29 − 9 =
  9. 9.70 + 19 =
  10. 10.52 + 9 =
  11. 11.34 + 9 =
  12. 12.339 + 99 =
  13. 13.21 + 19 =
  14. 14.50 − 9 =
  15. 15.12 + 9 =
  16. 16.59 + 19 =
  17. 17.22 + 19 =
  18. 18.501 + 99 =
  19. 19.81 − 9 =
  20. 20.44 + 29 =
  21. 21.73 + 19 =
  22. 22.145 + 99 =
  23. 23.47 − 9 =
  24. 24.37 − 29 =
  25. 25.59 − 19 =
  26. 26.109 + 99 =
  27. 27.31 + 29 =
  28. 28.43 − 9 =
  29. 29.196 + 99 =
  30. 30.92 − 19 =
  31. 31.32 + 9 =
  32. 32.251 − 99 =
  33. 33.389 − 99 =
  34. 34.840 − 99 =
  35. 35.72 + 9 =
  36. 36.271 − 99 =
  37. 37.52 + 29 =
  38. 38.28 − 19 =
  39. 39.60 + 19 =
  40. 40.833 − 99 =

Answer key

  1. 40
  2. 93
  3. 235
  4. 34
  5. 53
  6. 78
  7. 38
  8. 20
  9. 89
  10. 61
  11. 43
  12. 438
  13. 40
  14. 41
  15. 21
  16. 78
  17. 41
  18. 600
  19. 72
  20. 73
  21. 92
  22. 244
  23. 38
  24. 8
  25. 40
  26. 208
  27. 60
  28. 34
  29. 295
  30. 73
  31. 41
  32. 152
  33. 290
  34. 741
  35. 81
  36. 172
  37. 81
  38. 9
  39. 79
  40. 734

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