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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 215 · 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.?426 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.36?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?002 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?307 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?721 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 33 and take away the sum of its digits. What do you get?
  7. 7.Take 16 and take away the sum of its digits. What do you get?
  8. 8.62?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 72 and take away the sum of its digits. What do you get?
  10. 10.35?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?915 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 67 and take away the sum of its digits. What do you get?
  15. 15.2?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.670? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.500? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 14 and take away the sum of its digits. What do you get?
  19. 19.Take 79 and take away the sum of its digits. What do you get?
  20. 20.2?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.2?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.2?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?439 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 84 and take away the sum of its digits. What do you get?
  27. 27.Take 49 and take away the sum of its digits. What do you get?
  28. 28.61? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 74 and take away the sum of its digits. What do you get?
  31. 31.56?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.20?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.691? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?012 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.85?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 89 and take away the sum of its digits. What do you get?
  39. 39.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.23?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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