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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 32 · 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.Take 68 and take away the sum of its digits. What do you get?
  2. 2.Take 33 and take away the sum of its digits. What do you get?
  3. 3.60?2 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 61 and take away the sum of its digits. What do you get?
  6. 6.555? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 54 and take away the sum of its digits. What do you get?
  9. 9.?626 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 13 and take away the sum of its digits. What do you get?
  12. 12.Take 69 and take away the sum of its digits. What do you get?
  13. 13.4?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?548 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 12 and take away the sum of its digits. What do you get?
  16. 16.?780 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 89 and take away the sum of its digits. What do you get?
  18. 18.12?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 22 and take away the sum of its digits. What do you get?
  20. 20.Take 35 and take away the sum of its digits. What do you get?
  21. 21.111? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 27 and take away the sum of its digits. What do you get?
  23. 23.?863 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.78?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?772 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.412? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 30 and take away the sum of its digits. What do you get?
  29. 29.?897 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 83 and take away the sum of its digits. What do you get?
  31. 31.Take 74 and take away the sum of its digits. What do you get?
  32. 32.6?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 57 and take away the sum of its digits. What do you get?
  34. 34.?481 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?107 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.18?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.556? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.62?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 26 and take away the sum of its digits. What do you get?

Answer key

  1. 54
  2. 27
  3. 1
  4. 9
  5. 54
  6. 3
  7. 2
  8. 45
  9. 4
  10. 9
  11. 9
  12. 54
  13. 2
  14. 1
  15. 9
  16. 3
  17. 72
  18. 3
  19. 18
  20. 27
  21. 6
  22. 18
  23. 1
  24. 5
  25. 1
  26. 2
  27. 2
  28. 27
  29. 3
  30. 72
  31. 63
  32. 6
  33. 45
  34. 5
  35. 1
  36. 9
  37. 9
  38. 2
  39. 7
  40. 18

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