← 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 898 · 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. 1.52 + 29 =
  2. 2.620 + 99 =
  3. 3.286 + 99 =
  4. 4.41 + 19 =
  5. 5.13 − 9 =
  6. 6.63 + 19 =
  7. 7.41 − 19 =
  8. 8.25 + 19 =
  9. 9.91 − 29 =
  10. 10.16 + 29 =
  11. 11.15 − 9 =
  12. 12.80 − 19 =
  13. 13.527 + 99 =
  14. 14.74 + 29 =
  15. 15.14 + 9 =
  16. 16.54 + 19 =
  17. 17.49 + 29 =
  18. 18.58 − 19 =
  19. 19.366 − 99 =
  20. 20.14 − 9 =
  21. 21.75 − 29 =
  22. 22.27 + 19 =
  23. 23.19 − 9 =
  24. 24.50 + 9 =
  25. 25.405 − 99 =
  26. 26.15 + 19 =
  27. 27.34 − 9 =
  28. 28.635 − 99 =
  29. 29.34 + 9 =
  30. 30.898 − 99 =
  31. 31.43 + 9 =
  32. 32.41 + 9 =
  33. 33.48 − 19 =
  34. 34.53 − 9 =
  35. 35.465 − 99 =
  36. 36.45 + 9 =
  37. 37.61 − 19 =
  38. 38.42 + 9 =
  39. 39.181 + 99 =
  40. 40.71 + 19 =

Answer key

  1. 81
  2. 719
  3. 385
  4. 60
  5. 4
  6. 82
  7. 22
  8. 44
  9. 62
  10. 45
  11. 6
  12. 61
  13. 626
  14. 103
  15. 23
  16. 73
  17. 78
  18. 39
  19. 267
  20. 5
  21. 46
  22. 46
  23. 10
  24. 59
  25. 306
  26. 34
  27. 25
  28. 536
  29. 43
  30. 799
  31. 52
  32. 50
  33. 29
  34. 44
  35. 366
  36. 54
  37. 42
  38. 51
  39. 280
  40. 90

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