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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 295 · 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.?710 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.56?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.532? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?610 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?447 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 27 and take away the sum of its digits. What do you get?
  7. 7.246? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 77 and take away the sum of its digits. What do you get?
  9. 9.8?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.3?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.36?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 20 and take away the sum of its digits. What do you get?
  15. 15.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.88?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.4?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 91 and take away the sum of its digits. What do you get?
  19. 19.Take 62 and take away the sum of its digits. What do you get?
  20. 20.460? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.47?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 46 and take away the sum of its digits. What do you get?
  23. 23.7?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 24 and take away the sum of its digits. What do you get?
  27. 27.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.84?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?345 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?192 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.?907 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 44 and take away the sum of its digits. What do you get?
  35. 35.Take 31 and take away the sum of its digits. What do you get?
  36. 36.22?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.330? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 15 and take away the sum of its digits. What do you get?
  39. 39.361? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?296 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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