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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 805 · 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.?596 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 53 and take away the sum of its digits. What do you get?
  3. 3.82? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 15 and take away the sum of its digits. What do you get?
  5. 5.?371 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 38 and take away the sum of its digits. What do you get?
  7. 7.?839 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.82?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 45 and take away the sum of its digits. What do you get?
  10. 10.19?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 31 and take away the sum of its digits. What do you get?
  13. 13.3?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.6?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.889? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.72? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?863 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.7?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.73?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 63 and take away the sum of its digits. What do you get?
  24. 24.?862 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.4?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?418 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?880 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?311 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 20 and take away the sum of its digits. What do you get?
  31. 31.368? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 29 and take away the sum of its digits. What do you get?
  33. 33.1?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.24?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?172 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.77? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?462 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 43 and take away the sum of its digits. What do you get?
  39. 39.Take 52 and take away the sum of its digits. What do you get?
  40. 40.882? 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. 45
  3. 8
  4. 9
  5. 7
  6. 27
  7. 7
  8. 2
  9. 36
  10. 4
  11. 2
  12. 27
  13. 5
  14. 6
  15. 2
  16. 8
  17. 9
  18. 1
  19. 4
  20. 7
  21. 6
  22. 1
  23. 54
  24. 2
  25. 7
  26. 5
  27. 2
  28. 4
  29. 3
  30. 18
  31. 1
  32. 18
  33. 1
  34. 3
  35. 8
  36. 4
  37. 6
  38. 36
  39. 45
  40. 9

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