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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 84 · 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. 1.31?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.7?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.77? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 34 and take away the sum of its digits. What do you get?
  5. 5.Take 24 and take away the sum of its digits. What do you get?
  6. 6.4?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 99 and take away the sum of its digits. What do you get?
  8. 8.?004 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?289 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 66 and take away the sum of its digits. What do you get?
  11. 11.?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 26 and take away the sum of its digits. What do you get?
  13. 13.Take 33 and take away the sum of its digits. What do you get?
  14. 14.?336 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?114 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?204 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 93 and take away the sum of its digits. What do you get?
  18. 18.Take 95 and take away the sum of its digits. What do you get?
  19. 19.?451 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 64 and take away the sum of its digits. What do you get?
  21. 21.Take 38 and take away the sum of its digits. What do you get?
  22. 22.Take 37 and take away the sum of its digits. What do you get?
  23. 23.?983 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 94 and take away the sum of its digits. What do you get?
  25. 25.2?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 20 and take away the sum of its digits. What do you get?
  27. 27.68?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.1?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.7?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.13?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 23 and take away the sum of its digits. What do you get?
  32. 32.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 88 and take away the sum of its digits. What do you get?
  34. 34.66?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?079 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?871 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 85 and take away the sum of its digits. What do you get?
  40. 40.68? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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