← 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 342 · 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. 1.53 − 9 =
  2. 2.627 − 99 =
  3. 3.15 + 9 =
  4. 4.69 − 19 =
  5. 5.44 − 9 =
  6. 6.99 − 19 =
  7. 7.55 + 9 =
  8. 8.48 + 29 =
  9. 9.205 + 99 =
  10. 10.86 − 19 =
  11. 11.14 − 9 =
  12. 12.359 + 99 =
  13. 13.93 − 29 =
  14. 14.89 − 19 =
  15. 15.84 − 9 =
  16. 16.45 + 19 =
  17. 17.485 − 99 =
  18. 18.69 + 29 =
  19. 19.46 + 29 =
  20. 20.789 + 99 =
  21. 21.465 + 99 =
  22. 22.412 − 99 =
  23. 23.238 + 99 =
  24. 24.56 − 19 =
  25. 25.96 − 29 =
  26. 26.41 − 9 =
  27. 27.67 + 19 =
  28. 28.383 + 99 =
  29. 29.77 + 9 =
  30. 30.599 − 99 =
  31. 31.79 − 9 =
  32. 32.774 − 99 =
  33. 33.59 + 19 =
  34. 34.284 − 99 =
  35. 35.31 − 9 =
  36. 36.35 + 29 =
  37. 37.32 + 9 =
  38. 38.21 − 9 =
  39. 39.54 + 9 =
  40. 40.51 + 9 =

Answer key

  1. 44
  2. 528
  3. 24
  4. 50
  5. 35
  6. 80
  7. 64
  8. 77
  9. 304
  10. 67
  11. 5
  12. 458
  13. 64
  14. 70
  15. 75
  16. 64
  17. 386
  18. 98
  19. 75
  20. 888
  21. 564
  22. 313
  23. 337
  24. 37
  25. 67
  26. 32
  27. 86
  28. 482
  29. 86
  30. 500
  31. 70
  32. 675
  33. 78
  34. 185
  35. 22
  36. 64
  37. 41
  38. 12
  39. 63
  40. 60

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