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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 512 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.119? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.3?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 16 and take away the sum of its digits. What do you get?
  5. 5.Take 70 and take away the sum of its digits. What do you get?
  6. 6.649? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?335 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.800? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.44? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 88 and take away the sum of its digits. What do you get?
  11. 11.40?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.82?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 33 and take away the sum of its digits. What do you get?
  16. 16.Take 75 and take away the sum of its digits. What do you get?
  17. 17.4?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 65 and take away the sum of its digits. What do you get?
  19. 19.10?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 87 and take away the sum of its digits. What do you get?
  21. 21.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.56?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.82?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.9?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.22?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?133 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 15 and take away the sum of its digits. What do you get?
  29. 29.3?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 60 and take away the sum of its digits. What do you get?
  31. 31.Take 99 and take away the sum of its digits. What do you get?
  32. 32.21?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.784? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?206 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 42 and take away the sum of its digits. What do you get?
  38. 38.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.2?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.2?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 8
  3. 4
  4. 9
  5. 63
  6. 8
  7. 7
  8. 1
  9. 1
  10. 72
  11. 5
  12. 9
  13. 3
  14. 3
  15. 27
  16. 63
  17. 4
  18. 54
  19. 3
  20. 72
  21. 8
  22. 6
  23. 4
  24. 2
  25. 8
  26. 2
  27. 8
  28. 9
  29. 2
  30. 54
  31. 81
  32. 9
  33. 8
  34. 3
  35. 1
  36. 6
  37. 36
  38. 9
  39. 8
  40. 9

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