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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 533 · 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.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 22 and take away the sum of its digits. What do you get?
  3. 3.Take 42 and take away the sum of its digits. What do you get?
  4. 4.227? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 14 and take away the sum of its digits. What do you get?
  6. 6.31?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 94 and take away the sum of its digits. What do you get?
  8. 8.897? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.1?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 95 and take away the sum of its digits. What do you get?
  13. 13.?752 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 27 and take away the sum of its digits. What do you get?
  15. 15.18?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.155? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.56?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.840? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?596 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 32 and take away the sum of its digits. What do you get?
  22. 22.Take 45 and take away the sum of its digits. What do you get?
  23. 23.Take 64 and take away the sum of its digits. What do you get?
  24. 24.Take 62 and take away the sum of its digits. What do you get?
  25. 25.679? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.484? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 28 and take away the sum of its digits. What do you get?
  28. 28.170? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?848 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.82?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?908 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.68?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 55 and take away the sum of its digits. What do you get?
  36. 36.6?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?048 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.34?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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