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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 699 · 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 52 and take away the sum of its digits. What do you get?
  2. 2.44? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 69 and take away the sum of its digits. What do you get?
  4. 4.41?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.86?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 60 and take away the sum of its digits. What do you get?
  7. 7.?994 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.438? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.70?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.230? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 20 and take away the sum of its digits. What do you get?
  12. 12.Take 14 and take away the sum of its digits. What do you get?
  13. 13.?808 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.18?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.3?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?976 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.775? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.39?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.7?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.556? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 84 and take away the sum of its digits. What do you get?
  24. 24.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 76 and take away the sum of its digits. What do you get?
  29. 29.35?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?392 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.134? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 54 and take away the sum of its digits. What do you get?
  33. 33.?011 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?655 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.234? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?267 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.130? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 67 and take away the sum of its digits. What do you get?
  39. 39.Take 55 and take away the sum of its digits. What do you get?
  40. 40.1?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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