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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 992 · 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 13 and take away the sum of its digits. What do you get?
  2. 2.547? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?941 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?617 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 56 and take away the sum of its digits. What do you get?
  6. 6.?430 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.1?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 47 and take away the sum of its digits. What do you get?
  10. 10.4?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 99 and take away the sum of its digits. What do you get?
  12. 12.4?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 81 and take away the sum of its digits. What do you get?
  15. 15.?934 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.739? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 38 and take away the sum of its digits. What do you get?
  18. 18.6?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.19?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.844? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 18 and take away the sum of its digits. What do you get?
  22. 22.?541 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?436 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?305 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.483? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 76 and take away the sum of its digits. What do you get?
  29. 29.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?862 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.1?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.78? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 32 and take away the sum of its digits. What do you get?
  34. 34.?527 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.79?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?686 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?653 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.245? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.654? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.88?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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