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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 455 · 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. 1.662? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.11?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.6?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.1?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 37 and take away the sum of its digits. What do you get?
  7. 7.Take 85 and take away the sum of its digits. What do you get?
  8. 8.2?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 11 and take away the sum of its digits. What do you get?
  10. 10.Take 21 and take away the sum of its digits. What do you get?
  11. 11.?016 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 60 and take away the sum of its digits. What do you get?
  14. 14.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 86 and take away the sum of its digits. What do you get?
  16. 16.?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 96 and take away the sum of its digits. What do you get?
  18. 18.Take 98 and take away the sum of its digits. What do you get?
  19. 19.?508 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 76 and take away the sum of its digits. What do you get?
  21. 21.Take 14 and take away the sum of its digits. What do you get?
  22. 22.202? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 72 and take away the sum of its digits. What do you get?
  24. 24.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 77 and take away the sum of its digits. What do you get?
  26. 26.3?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.74?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 27 and take away the sum of its digits. What do you get?
  29. 29.340? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.40?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?903 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.6?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?275 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.400? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.149? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.1?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?373 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.22?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.7?98 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. 4
  3. 2
  4. 4
  5. 8
  6. 27
  7. 72
  8. 1
  9. 9
  10. 18
  11. 2
  12. 6
  13. 54
  14. 4
  15. 72
  16. 4
  17. 81
  18. 81
  19. 5
  20. 63
  21. 9
  22. 5
  23. 63
  24. 1
  25. 63
  26. 6
  27. 7
  28. 18
  29. 2
  30. 3
  31. 6
  32. 1
  33. 5
  34. 4
  35. 5
  36. 4
  37. 1
  38. 5
  39. 2
  40. 3

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