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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 721 · 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.Take 41 and take away the sum of its digits. What do you get?
  2. 2.28?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.659? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.698? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 51 and take away the sum of its digits. What do you get?
  6. 6.Take 95 and take away the sum of its digits. What do you get?
  7. 7.2?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?160 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 16 and take away the sum of its digits. What do you get?
  10. 10.6?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.622? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.881? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.383? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.46?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?697 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 50 and take away the sum of its digits. What do you get?
  18. 18.?375 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 65 and take away the sum of its digits. What do you get?
  20. 20.?263 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.28? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?751 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 89 and take away the sum of its digits. What do you get?
  24. 24.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.6?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?795 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?181 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.115? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.36?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.899? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 77 and take away the sum of its digits. What do you get?
  34. 34.?898 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.38?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.56?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.191? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.42?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 81 and take away the sum of its digits. What do you get?

Answer key

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

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