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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 566 · 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.?716 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 46 and take away the sum of its digits. What do you get?
  3. 3.6?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?109 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.13?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.5?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 65 and take away the sum of its digits. What do you get?
  8. 8.Take 34 and take away the sum of its digits. What do you get?
  9. 9.Take 87 and take away the sum of its digits. What do you get?
  10. 10.5?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 69 and take away the sum of its digits. What do you get?
  12. 12.74?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 49 and take away the sum of its digits. What do you get?
  14. 14.8?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?449 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.3?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.27?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?980 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 91 and take away the sum of its digits. What do you get?
  21. 21.17? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.710? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.10?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.8?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.49?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.195? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?907 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 53 and take away the sum of its digits. What do you get?
  29. 29.Take 97 and take away the sum of its digits. What do you get?
  30. 30.864? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 36 and take away the sum of its digits. What do you get?
  32. 32.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?831 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 90 and take away the sum of its digits. What do you get?
  36. 36.704? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?146 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?581 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.4?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 47 and take away the sum of its digits. What do you get?

Answer key

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

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