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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 944 · 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. 1.19?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 16 and take away the sum of its digits. What do you get?
  4. 4.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.70?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?265 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 58 and take away the sum of its digits. What do you get?
  8. 8.13?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.612? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 84 and take away the sum of its digits. What do you get?
  11. 11.8?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?742 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 28 and take away the sum of its digits. What do you get?
  14. 14.?681 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?923 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?731 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.511? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.89? 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. 22.4?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?996 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 31 and take away the sum of its digits. What do you get?
  25. 25.41?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.583? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.2?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.172? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.27?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 52 and take away the sum of its digits. What do you get?
  31. 31.43?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.271? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?286 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?116 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.17?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 68 and take away the sum of its digits. What do you get?
  37. 37.50?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.8?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 73 and take away the sum of its digits. What do you get?

Answer key

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

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