← 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 811 · 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. 1.28 − 9 =
  2. 2.498 − 99 =
  3. 3.244 + 99 =
  4. 4.60 + 19 =
  5. 5.45 + 19 =
  6. 6.324 + 99 =
  7. 7.58 + 9 =
  8. 8.33 + 19 =
  9. 9.16 + 19 =
  10. 10.46 − 29 =
  11. 11.242 + 99 =
  12. 12.76 − 9 =
  13. 13.38 + 9 =
  14. 14.24 + 29 =
  15. 15.317 − 99 =
  16. 16.89 − 29 =
  17. 17.97 − 19 =
  18. 18.70 + 9 =
  19. 19.64 − 19 =
  20. 20.16 + 29 =
  21. 21.12 − 9 =
  22. 22.62 + 9 =
  23. 23.73 − 9 =
  24. 24.33 + 9 =
  25. 25.35 + 9 =
  26. 26.12 + 19 =
  27. 27.75 − 9 =
  28. 28.384 + 99 =
  29. 29.774 − 99 =
  30. 30.18 + 9 =
  31. 31.15 + 19 =
  32. 32.62 − 9 =
  33. 33.30 + 29 =
  34. 34.70 − 19 =
  35. 35.66 − 19 =
  36. 36.215 − 99 =
  37. 37.696 − 99 =
  38. 38.24 + 19 =
  39. 39.80 + 19 =
  40. 40.22 − 9 =

Answer key

  1. 19
  2. 399
  3. 343
  4. 79
  5. 64
  6. 423
  7. 67
  8. 52
  9. 35
  10. 17
  11. 341
  12. 67
  13. 47
  14. 53
  15. 218
  16. 60
  17. 78
  18. 79
  19. 45
  20. 45
  21. 3
  22. 71
  23. 64
  24. 42
  25. 44
  26. 31
  27. 66
  28. 483
  29. 675
  30. 27
  31. 34
  32. 53
  33. 59
  34. 51
  35. 47
  36. 116
  37. 597
  38. 43
  39. 99
  40. 13

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