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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 774 · 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.?440 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 95 and take away the sum of its digits. What do you get?
  3. 3.5?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.160? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 92 and take away the sum of its digits. What do you get?
  6. 6.37?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 35 and take away the sum of its digits. What do you get?
  8. 8.3?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.692? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 83 and take away the sum of its digits. What do you get?
  11. 11.Take 50 and take away the sum of its digits. What do you get?
  12. 12.?393 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.1?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.641? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?470 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.55?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?896 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.1?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.47? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.3?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 69 and take away the sum of its digits. What do you get?
  22. 22.?403 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.11?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.220? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?380 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?876 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.19?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 15 and take away the sum of its digits. What do you get?
  29. 29.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 98 and take away the sum of its digits. What do you get?
  31. 31.Take 72 and take away the sum of its digits. What do you get?
  32. 32.Take 52 and take away the sum of its digits. What do you get?
  33. 33.Take 37 and take away the sum of its digits. What do you get?
  34. 34.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 17 and take away the sum of its digits. What do you get?
  36. 36.Take 41 and take away the sum of its digits. What do you get?
  37. 37.87?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.86?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?665 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. 81
  3. 2
  4. 2
  5. 81
  6. 2
  7. 27
  8. 6
  9. 1
  10. 72
  11. 45
  12. 3
  13. 6
  14. 7
  15. 7
  16. 7
  17. 4
  18. 9
  19. 7
  20. 7
  21. 54
  22. 2
  23. 1
  24. 5
  25. 7
  26. 6
  27. 7
  28. 9
  29. 9
  30. 81
  31. 63
  32. 45
  33. 27
  34. 2
  35. 9
  36. 36
  37. 9
  38. 1
  39. 5
  40. 1

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