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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 659 · 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 88 and take away the sum of its digits. What do you get?
  2. 2.30?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 60 and take away the sum of its digits. What do you get?
  4. 4.?083 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?425 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 48 and take away the sum of its digits. What do you get?
  9. 9.84? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.5?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 16 and take away the sum of its digits. What do you get?
  12. 12.?498 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.560? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.63?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.24?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.88?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 90 and take away the sum of its digits. What do you get?
  18. 18.Take 40 and take away the sum of its digits. What do you get?
  19. 19.Take 64 and take away the sum of its digits. What do you get?
  20. 20.28?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.8?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.45?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 14 and take away the sum of its digits. What do you get?
  24. 24.2?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 11 and take away the sum of its digits. What do you get?
  26. 26.10?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?986 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 45 and take away the sum of its digits. What do you get?
  29. 29.?308 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 87 and take away the sum of its digits. What do you get?
  31. 31.Take 61 and take away the sum of its digits. What do you get?
  32. 32.Take 71 and take away the sum of its digits. What do you get?
  33. 33.704? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 32 and take away the sum of its digits. What do you get?
  35. 35.?988 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?218 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.499? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 59 and take away the sum of its digits. What do you get?

Answer key

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

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