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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 666 · 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 78 and take away the sum of its digits. What do you get?
  2. 2.116? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 93 and take away the sum of its digits. What do you get?
  4. 4.62?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 41 and take away the sum of its digits. What do you get?
  6. 6.Take 77 and take away the sum of its digits. What do you get?
  7. 7.Take 27 and take away the sum of its digits. What do you get?
  8. 8.Take 21 and take away the sum of its digits. What do you get?
  9. 9.?443 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.1?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.780? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?770 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.630? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?724 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.46?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?719 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?191 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 35 and take away the sum of its digits. What do you get?
  21. 21.7?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?481 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.52?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?688 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 26 and take away the sum of its digits. What do you get?
  27. 27.Take 61 and take away the sum of its digits. What do you get?
  28. 28.88?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 98 and take away the sum of its digits. What do you get?
  30. 30.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 34 and take away the sum of its digits. What do you get?
  33. 33.803? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.138? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.33?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?709 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?331 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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