← 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 353 · 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. 1.54 − 19 =
  2. 2.38 + 9 =
  3. 3.58 − 19 =
  4. 4.384 − 99 =
  5. 5.42 − 29 =
  6. 6.48 + 29 =
  7. 7.77 − 9 =
  8. 8.38 + 29 =
  9. 9.56 + 9 =
  10. 10.13 − 9 =
  11. 11.13 + 19 =
  12. 12.36 − 9 =
  13. 13.436 + 99 =
  14. 14.69 + 19 =
  15. 15.79 + 19 =
  16. 16.57 − 29 =
  17. 17.56 − 29 =
  18. 18.50 + 9 =
  19. 19.160 + 99 =
  20. 20.797 + 99 =
  21. 21.36 + 9 =
  22. 22.46 − 29 =
  23. 23.93 − 19 =
  24. 24.50 − 9 =
  25. 25.53 + 19 =
  26. 26.168 − 99 =
  27. 27.426 − 99 =
  28. 28.270 + 99 =
  29. 29.268 + 99 =
  30. 30.14 + 9 =
  31. 31.69 + 9 =
  32. 32.97 − 29 =
  33. 33.17 + 9 =
  34. 34.22 + 19 =
  35. 35.57 − 9 =
  36. 36.57 + 9 =
  37. 37.716 − 99 =
  38. 38.34 + 19 =
  39. 39.18 + 19 =
  40. 40.28 + 9 =

Answer key

  1. 35
  2. 47
  3. 39
  4. 285
  5. 13
  6. 77
  7. 68
  8. 67
  9. 65
  10. 4
  11. 32
  12. 27
  13. 535
  14. 88
  15. 98
  16. 28
  17. 27
  18. 59
  19. 259
  20. 896
  21. 45
  22. 17
  23. 74
  24. 41
  25. 72
  26. 69
  27. 327
  28. 369
  29. 367
  30. 23
  31. 78
  32. 68
  33. 26
  34. 41
  35. 48
  36. 66
  37. 617
  38. 53
  39. 37
  40. 37

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