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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 735 · 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. 1.7?02 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. 3.73?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.29? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.40?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 26 and take away the sum of its digits. What do you get?
  7. 7.58?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 47 and take away the sum of its digits. What do you get?
  9. 9.Take 98 and take away the sum of its digits. What do you get?
  10. 10.Take 28 and take away the sum of its digits. What do you get?
  11. 11.Take 87 and take away the sum of its digits. What do you get?
  12. 12.482? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?605 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.6?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 30 and take away the sum of its digits. What do you get?
  16. 16.Take 79 and take away the sum of its digits. What do you get?
  17. 17.Take 65 and take away the sum of its digits. What do you get?
  18. 18.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.288? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.115? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.860? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.56?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.82?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?381 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.411? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 76 and take away the sum of its digits. What do you get?
  27. 27.?502 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.19?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?640 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.77?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 35 and take away the sum of its digits. What do you get?
  32. 32.Take 91 and take away the sum of its digits. What do you get?
  33. 33.2?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.783? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.17?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 52 and take away the sum of its digits. What do you get?
  38. 38.6?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 12 and take away the sum of its digits. What do you get?

Answer key

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

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