← 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 463 · 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. 1.57 + 19 =
  2. 2.345 + 99 =
  3. 3.53 − 29 =
  4. 4.49 + 9 =
  5. 5.77 − 29 =
  6. 6.74 − 9 =
  7. 7.37 − 19 =
  8. 8.91 − 19 =
  9. 9.201 + 99 =
  10. 10.49 − 29 =
  11. 11.41 + 19 =
  12. 12.18 − 9 =
  13. 13.107 − 29 =
  14. 14.40 + 19 =
  15. 15.12 + 9 =
  16. 16.37 − 9 =
  17. 17.67 − 9 =
  18. 18.34 − 29 =
  19. 19.613 − 99 =
  20. 20.55 − 9 =
  21. 21.46 − 29 =
  22. 22.497 + 99 =
  23. 23.45 − 29 =
  24. 24.55 + 9 =
  25. 25.228 + 99 =
  26. 26.87 − 29 =
  27. 27.54 + 19 =
  28. 28.623 − 99 =
  29. 29.58 + 29 =
  30. 30.44 + 19 =
  31. 31.64 + 19 =
  32. 32.265 + 99 =
  33. 33.87 − 9 =
  34. 34.58 + 9 =
  35. 35.185 + 99 =
  36. 36.25 − 9 =
  37. 37.74 − 19 =
  38. 38.532 − 99 =
  39. 39.33 − 29 =
  40. 40.62 + 29 =

Answer key

  1. 76
  2. 444
  3. 24
  4. 58
  5. 48
  6. 65
  7. 18
  8. 72
  9. 300
  10. 20
  11. 60
  12. 9
  13. 78
  14. 59
  15. 21
  16. 28
  17. 58
  18. 5
  19. 514
  20. 46
  21. 17
  22. 596
  23. 16
  24. 64
  25. 327
  26. 58
  27. 73
  28. 524
  29. 87
  30. 63
  31. 83
  32. 364
  33. 78
  34. 67
  35. 284
  36. 16
  37. 55
  38. 433
  39. 4
  40. 91

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