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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 709 · 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.?575 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.Take 94 and take away the sum of its digits. What do you get?
  4. 4.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 53 and take away the sum of its digits. What do you get?
  6. 6.827? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 24 and take away the sum of its digits. What do you get?
  8. 8.4?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?930 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 95 and take away the sum of its digits. What do you get?
  11. 11.49?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.762? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.329? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 83 and take away the sum of its digits. What do you get?
  15. 15.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?088 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 34 and take away the sum of its digits. What do you get?
  19. 19.4?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 84 and take away the sum of its digits. What do you get?
  21. 21.?478 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.8?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?341 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.15?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.116? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?968 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.736? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 92 and take away the sum of its digits. What do you get?
  30. 30.547? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.32?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.68?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.39?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 85 and take away the sum of its digits. What do you get?
  36. 36.?950 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?602 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?419 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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