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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 373 · 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. 1.63?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.1?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 76 and take away the sum of its digits. What do you get?
  6. 6.?655 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 36 and take away the sum of its digits. What do you get?
  8. 8.Take 96 and take away the sum of its digits. What do you get?
  9. 9.?320 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 86 and take away the sum of its digits. What do you get?
  11. 11.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 83 and take away the sum of its digits. What do you get?
  13. 13.869? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 29 and take away the sum of its digits. What do you get?
  15. 15.2?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.322? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?870 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.515? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.8?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.81?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?968 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.46?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 16 and take away the sum of its digits. What do you get?
  26. 26.Take 84 and take away the sum of its digits. What do you get?
  27. 27.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 70 and take away the sum of its digits. What do you get?
  30. 30.Take 13 and take away the sum of its digits. What do you get?
  31. 31.?956 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.9?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?289 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 37 and take away the sum of its digits. What do you get?
  36. 36.542? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.578? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.6?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.428? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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