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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 122 · 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. 1.82?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?125 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?548 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.43?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 48 and take away the sum of its digits. What do you get?
  6. 6.889? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 75 and take away the sum of its digits. What do you get?
  8. 8.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.57?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?149 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.128? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 37 and take away the sum of its digits. What do you get?
  13. 13.?056 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.2?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.801? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.477? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?766 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.47?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?933 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.79?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?322 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.237? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.213? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.9?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.1?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 79 and take away the sum of its digits. What do you get?
  31. 31.Take 35 and take away the sum of its digits. What do you get?
  32. 32.4?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 19 and take away the sum of its digits. What do you get?
  34. 34.8?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?890 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.55?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.624? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.418? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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