← 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 455 · 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. 1.56 − 9 =
  2. 2.20 + 9 =
  3. 3.20 + 19 =
  4. 4.26 − 19 =
  5. 5.37 + 9 =
  6. 6.74 + 9 =
  7. 7.34 + 29 =
  8. 8.770 − 99 =
  9. 9.346 + 99 =
  10. 10.355 + 99 =
  11. 11.70 + 19 =
  12. 12.189 + 99 =
  13. 13.507 + 99 =
  14. 14.13 + 9 =
  15. 15.356 − 99 =
  16. 16.77 − 29 =
  17. 17.43 + 19 =
  18. 18.22 + 9 =
  19. 19.20 + 29 =
  20. 20.65 + 29 =
  21. 21.67 + 19 =
  22. 22.95 − 29 =
  23. 23.28 − 9 =
  24. 24.18 + 9 =
  25. 25.13 − 9 =
  26. 26.79 + 9 =
  27. 27.32 + 19 =
  28. 28.66 + 9 =
  29. 29.103 − 29 =
  30. 30.65 + 19 =
  31. 31.223 + 99 =
  32. 32.60 + 9 =
  33. 33.12 + 9 =
  34. 34.49 − 29 =
  35. 35.230 + 99 =
  36. 36.77 − 9 =
  37. 37.75 − 9 =
  38. 38.73 + 9 =
  39. 39.432 − 99 =
  40. 40.16 + 29 =

Answer key

  1. 47
  2. 29
  3. 39
  4. 7
  5. 46
  6. 83
  7. 63
  8. 671
  9. 445
  10. 454
  11. 89
  12. 288
  13. 606
  14. 22
  15. 257
  16. 48
  17. 62
  18. 31
  19. 49
  20. 94
  21. 86
  22. 66
  23. 19
  24. 27
  25. 4
  26. 88
  27. 51
  28. 75
  29. 74
  30. 84
  31. 322
  32. 69
  33. 21
  34. 20
  35. 329
  36. 68
  37. 66
  38. 82
  39. 333
  40. 45

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