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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 977 · 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. 1.3?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 36 and take away the sum of its digits. What do you get?
  3. 3.?786 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 98 and take away the sum of its digits. What do you get?
  5. 5.276? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.731? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.22?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 23 and take away the sum of its digits. What do you get?
  11. 11.?267 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 65 and take away the sum of its digits. What do you get?
  13. 13.Take 16 and take away the sum of its digits. What do you get?
  14. 14.262? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 49 and take away the sum of its digits. What do you get?
  16. 16.Take 14 and take away the sum of its digits. What do you get?
  17. 17.251? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.3?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 21 and take away the sum of its digits. What do you get?
  20. 20.Take 89 and take away the sum of its digits. What do you get?
  21. 21.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.88?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?575 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?355 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.469? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?059 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.86?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.12?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.2?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 48 and take away the sum of its digits. What do you get?
  31. 31.70?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 94 and take away the sum of its digits. What do you get?
  33. 33.70? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.440? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 44 and take away the sum of its digits. What do you get?
  36. 36.59?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 55 and take away the sum of its digits. What do you get?
  38. 38.1?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?984 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?312 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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