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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 511 · 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 34 and take away the sum of its digits. What do you get?
  2. 2.23?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 26 and take away the sum of its digits. What do you get?
  4. 4.Take 68 and take away the sum of its digits. What do you get?
  5. 5.Take 45 and take away the sum of its digits. What do you get?
  6. 6.3?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 73 and take away the sum of its digits. What do you get?
  8. 8.Take 93 and take away the sum of its digits. What do you get?
  9. 9.Take 80 and take away the sum of its digits. What do you get?
  10. 10.86?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.32?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?402 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 69 and take away the sum of its digits. What do you get?
  14. 14.?250 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.7?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 70 and take away the sum of its digits. What do you get?
  17. 17.592? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 31 and take away the sum of its digits. What do you get?
  19. 19.Take 51 and take away the sum of its digits. What do you get?
  20. 20.?035 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?941 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.63? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.46?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?929 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.2?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.88?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 96 and take away the sum of its digits. What do you get?
  28. 28.?946 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 72 and take away the sum of its digits. What do you get?
  30. 30.858? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.579? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?553 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 30 and take away the sum of its digits. What do you get?
  34. 34.678? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.5?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.55?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.13?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.311? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 71 and take away the sum of its digits. What do you get?
  40. 40.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 27
  2. 2
  3. 18
  4. 54
  5. 36
  6. 3
  7. 63
  8. 81
  9. 72
  10. 3
  11. 4
  12. 3
  13. 54
  14. 2
  15. 3
  16. 63
  17. 2
  18. 27
  19. 45
  20. 1
  21. 4
  22. 9
  23. 5
  24. 7
  25. 3
  26. 1
  27. 81
  28. 8
  29. 63
  30. 6
  31. 6
  32. 5
  33. 27
  34. 6
  35. 5
  36. 1
  37. 5
  38. 4
  39. 63
  40. 2

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