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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 832 · 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. 1.397? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?608 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.122? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?735 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.31?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.8?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.6?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 47 and take away the sum of its digits. What do you get?
  14. 14.?725 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 58 and take away the sum of its digits. What do you get?
  16. 16.Take 52 and take away the sum of its digits. What do you get?
  17. 17.25?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.20?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 42 and take away the sum of its digits. What do you get?
  20. 20.19?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 84 and take away the sum of its digits. What do you get?
  22. 22.?003 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?416 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 39 and take away the sum of its digits. What do you get?
  25. 25.?185 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.60?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 87 and take away the sum of its digits. What do you get?
  29. 29.32?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.22?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.468? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?241 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.340? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.206? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 99 and take away the sum of its digits. What do you get?
  37. 37.15?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 68 and take away the sum of its digits. What do you get?
  39. 39.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?187 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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