← 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 410 · 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. 1.31 + 19 =
  2. 2.32 − 19 =
  3. 3.42 + 19 =
  4. 4.584 − 99 =
  5. 5.361 − 99 =
  6. 6.75 + 29 =
  7. 7.17 + 9 =
  8. 8.497 + 99 =
  9. 9.719 + 99 =
  10. 10.72 + 9 =
  11. 11.13 + 29 =
  12. 12.29 + 9 =
  13. 13.519 + 99 =
  14. 14.206 + 99 =
  15. 15.167 − 99 =
  16. 16.13 + 19 =
  17. 17.25 + 9 =
  18. 18.61 + 29 =
  19. 19.91 − 29 =
  20. 20.50 + 29 =
  21. 21.34 + 29 =
  22. 22.785 + 99 =
  23. 23.529 + 99 =
  24. 24.12 + 9 =
  25. 25.65 + 29 =
  26. 26.99 − 19 =
  27. 27.44 − 9 =
  28. 28.27 + 9 =
  29. 29.69 − 9 =
  30. 30.58 − 29 =
  31. 31.56 + 29 =
  32. 32.668 + 99 =
  33. 33.55 + 29 =
  34. 34.46 + 9 =
  35. 35.60 − 19 =
  36. 36.60 + 9 =
  37. 37.39 + 9 =
  38. 38.188 − 99 =
  39. 39.29 + 19 =
  40. 40.183 + 99 =

Answer key

  1. 50
  2. 13
  3. 61
  4. 485
  5. 262
  6. 104
  7. 26
  8. 596
  9. 818
  10. 81
  11. 42
  12. 38
  13. 618
  14. 305
  15. 68
  16. 32
  17. 34
  18. 90
  19. 62
  20. 79
  21. 63
  22. 884
  23. 628
  24. 21
  25. 94
  26. 80
  27. 35
  28. 36
  29. 60
  30. 29
  31. 85
  32. 767
  33. 84
  34. 55
  35. 41
  36. 69
  37. 48
  38. 89
  39. 48
  40. 282

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