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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 746 · 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.?338 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 85 and take away the sum of its digits. What do you get?
  3. 3.354? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.609? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.24? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.4?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 31 and take away the sum of its digits. What do you get?
  8. 8.?390 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.87?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.793? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.2?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 34 and take away the sum of its digits. What do you get?
  16. 16.Take 70 and take away the sum of its digits. What do you get?
  17. 17.Take 48 and take away the sum of its digits. What do you get?
  18. 18.?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.796? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 55 and take away the sum of its digits. What do you get?
  21. 21.882? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 45 and take away the sum of its digits. What do you get?
  23. 23.?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 71 and take away the sum of its digits. What do you get?
  25. 25.Take 84 and take away the sum of its digits. What do you get?
  26. 26.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.38?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?608 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 18 and take away the sum of its digits. What do you get?
  30. 30.?091 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.3?3 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. 33.43? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.53?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 27 and take away the sum of its digits. What do you get?
  36. 36.6?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.177? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 19 and take away the sum of its digits. What do you get?
  39. 39.?053 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.757? 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. 72
  3. 6
  4. 3
  5. 3
  6. 3
  7. 27
  8. 6
  9. 1
  10. 1
  11. 9
  12. 5
  13. 8
  14. 1
  15. 27
  16. 63
  17. 36
  18. 3
  19. 5
  20. 45
  21. 9
  22. 36
  23. 4
  24. 63
  25. 72
  26. 3
  27. 3
  28. 4
  29. 9
  30. 8
  31. 3
  32. 81
  33. 2
  34. 1
  35. 18
  36. 6
  37. 3
  38. 9
  39. 1
  40. 8

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