← 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 735 · 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. 1.343 + 99 =
  2. 2.67 + 19 =
  3. 3.43 − 29 =
  4. 4.565 + 99 =
  5. 5.34 + 29 =
  6. 6.80 − 19 =
  7. 7.284 − 99 =
  8. 8.80 + 29 =
  9. 9.59 − 9 =
  10. 10.586 + 99 =
  11. 11.38 + 29 =
  12. 12.55 + 9 =
  13. 13.65 + 29 =
  14. 14.643 − 99 =
  15. 15.206 − 99 =
  16. 16.716 − 99 =
  17. 17.24 + 9 =
  18. 18.60 − 19 =
  19. 19.42 + 29 =
  20. 20.50 + 19 =
  21. 21.76 + 9 =
  22. 22.641 + 99 =
  23. 23.34 − 9 =
  24. 24.40 + 19 =
  25. 25.68 + 29 =
  26. 26.69 + 9 =
  27. 27.44 + 9 =
  28. 28.93 − 19 =
  29. 29.439 + 99 =
  30. 30.47 + 19 =
  31. 31.56 − 29 =
  32. 32.379 − 99 =
  33. 33.26 − 19 =
  34. 34.24 − 19 =
  35. 35.22 − 19 =
  36. 36.53 + 9 =
  37. 37.53 − 19 =
  38. 38.76 − 19 =
  39. 39.21 + 29 =
  40. 40.727 + 99 =

Answer key

  1. 442
  2. 86
  3. 14
  4. 664
  5. 63
  6. 61
  7. 185
  8. 109
  9. 50
  10. 685
  11. 67
  12. 64
  13. 94
  14. 544
  15. 107
  16. 617
  17. 33
  18. 41
  19. 71
  20. 69
  21. 85
  22. 740
  23. 25
  24. 59
  25. 97
  26. 78
  27. 53
  28. 74
  29. 538
  30. 66
  31. 27
  32. 280
  33. 7
  34. 5
  35. 3
  36. 62
  37. 34
  38. 57
  39. 50
  40. 826

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