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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 125 · 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. 1.28?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 66 and take away the sum of its digits. What do you get?
  3. 3.Take 19 and take away the sum of its digits. What do you get?
  4. 4.8?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.163? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?574 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 23 and take away the sum of its digits. What do you get?
  8. 8.?701 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.59? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.528? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.51?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?316 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?285 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 84 and take away the sum of its digits. What do you get?
  17. 17.526? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 96 and take away the sum of its digits. What do you get?
  19. 19.Take 87 and take away the sum of its digits. What do you get?
  20. 20.593? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.8?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.7?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.3?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.8?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.174? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 81 and take away the sum of its digits. What do you get?
  29. 29.819? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.4?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 61 and take away the sum of its digits. What do you get?
  33. 33.?070 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?718 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 74 and take away the sum of its digits. What do you get?
  36. 36.Take 37 and take away the sum of its digits. What do you get?
  37. 37.Take 44 and take away the sum of its digits. What do you get?
  38. 38.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.788? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.49?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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