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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 299 · 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. 1.39?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?651 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.42?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 75 and take away the sum of its digits. What do you get?
  5. 5.?663 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.Take 16 and take away the sum of its digits. What do you get?
  8. 8.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.62?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 65 and take away the sum of its digits. What do you get?
  11. 11.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?455 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 43 and take away the sum of its digits. What do you get?
  14. 14.Take 20 and take away the sum of its digits. What do you get?
  15. 15.Take 72 and take away the sum of its digits. What do you get?
  16. 16.?978 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.772? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 54 and take away the sum of its digits. What do you get?
  19. 19.Take 47 and take away the sum of its digits. What do you get?
  20. 20.8?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.6?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.71?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.4?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.89?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 99 and take away the sum of its digits. What do you get?
  28. 28.?098 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 11 and take away the sum of its digits. What do you get?
  31. 31.24? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.759? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 46 and take away the sum of its digits. What do you get?
  35. 35.8?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.738? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?899 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.6?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?968 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. 6
  3. 7
  4. 63
  5. 3
  6. 27
  7. 9
  8. 8
  9. 4
  10. 54
  11. 1
  12. 4
  13. 36
  14. 18
  15. 63
  16. 3
  17. 2
  18. 45
  19. 36
  20. 8
  21. 5
  22. 1
  23. 2
  24. 7
  25. 3
  26. 2
  27. 81
  28. 1
  29. 2
  30. 9
  31. 3
  32. 1
  33. 6
  34. 36
  35. 7
  36. 9
  37. 5
  38. 1
  39. 4
  40. 4

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