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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 22 · 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. 1.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?500 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.82?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 27 and take away the sum of its digits. What do you get?
  5. 5.2?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?196 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.7?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.86?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.778? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 70 and take away the sum of its digits. What do you get?
  11. 11.Take 83 and take away the sum of its digits. What do you get?
  12. 12.?023 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.13?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.422? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?905 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.481? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 22 and take away the sum of its digits. What do you get?
  19. 19.502? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 96 and take away the sum of its digits. What do you get?
  21. 21.?323 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.122? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 66 and take away the sum of its digits. What do you get?
  24. 24.Take 80 and take away the sum of its digits. What do you get?
  25. 25.Take 36 and take away the sum of its digits. What do you get?
  26. 26.8?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?331 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.187? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.846? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 81 and take away the sum of its digits. What do you get?
  32. 32.6?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.7?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.166? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 53 and take away the sum of its digits. What do you get?
  37. 37.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 59 and take away the sum of its digits. What do you get?
  39. 39.?930 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?003 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 5
  2. 4
  3. 5
  4. 18
  5. 7
  6. 2
  7. 4
  8. 5
  9. 5
  10. 63
  11. 72
  12. 4
  13. 9
  14. 1
  15. 1
  16. 4
  17. 5
  18. 18
  19. 2
  20. 81
  21. 1
  22. 4
  23. 54
  24. 72
  25. 27
  26. 6
  27. 3
  28. 2
  29. 2
  30. 9
  31. 72
  32. 5
  33. 6
  34. 8
  35. 5
  36. 45
  37. 8
  38. 45
  39. 6
  40. 6

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