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Adding 9, 19 and 99 Mental Maths Worksheet

Mental maths lesson 4: Add and take away 9, 19 and 99 · Set 652 · 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. 1.33 + 19 =
  2. 2.53 + 19 =
  3. 3.62 + 29 =
  4. 4.19 − 9 =
  5. 5.14 + 9 =
  6. 6.42 − 9 =
  7. 7.44 + 9 =
  8. 8.27 + 9 =
  9. 9.689 + 99 =
  10. 10.385 + 99 =
  11. 11.87 − 9 =
  12. 12.39 + 9 =
  13. 13.42 + 9 =
  14. 14.50 + 9 =
  15. 15.59 + 9 =
  16. 16.58 − 9 =
  17. 17.66 + 29 =
  18. 18.87 − 19 =
  19. 19.63 − 9 =
  20. 20.27 + 19 =
  21. 21.54 + 9 =
  22. 22.644 − 99 =
  23. 23.43 − 29 =
  24. 24.36 + 9 =
  25. 25.550 + 99 =
  26. 26.57 − 19 =
  27. 27.414 − 99 =
  28. 28.41 − 29 =
  29. 29.514 − 99 =
  30. 30.80 − 9 =
  31. 31.67 − 19 =
  32. 32.49 − 19 =
  33. 33.586 − 99 =
  34. 34.49 − 29 =
  35. 35.54 + 29 =
  36. 36.23 − 19 =
  37. 37.26 − 19 =
  38. 38.271 − 99 =
  39. 39.26 + 9 =
  40. 40.28 + 9 =

Answer key

  1. 52
  2. 72
  3. 91
  4. 10
  5. 23
  6. 33
  7. 53
  8. 36
  9. 788
  10. 484
  11. 78
  12. 48
  13. 51
  14. 59
  15. 68
  16. 49
  17. 95
  18. 68
  19. 54
  20. 46
  21. 63
  22. 545
  23. 14
  24. 45
  25. 649
  26. 38
  27. 315
  28. 12
  29. 415
  30. 71
  31. 48
  32. 30
  33. 487
  34. 20
  35. 83
  36. 4
  37. 7
  38. 172
  39. 35
  40. 37

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