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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 687 · 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 74 and take away the sum of its digits. What do you get?
  2. 2.Take 57 and take away the sum of its digits. What do you get?
  3. 3.Take 62 and take away the sum of its digits. What do you get?
  4. 4.27?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?660 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?193 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 48 and take away the sum of its digits. What do you get?
  9. 9.Take 12 and take away the sum of its digits. What do you get?
  10. 10.95? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?851 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.9?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.8?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?847 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.173? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.10?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 41 and take away the sum of its digits. What do you get?
  18. 18.821? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.4?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 21 and take away the sum of its digits. What do you get?
  21. 21.Take 23 and take away the sum of its digits. What do you get?
  22. 22.Take 24 and take away the sum of its digits. What do you get?
  23. 23.Take 45 and take away the sum of its digits. What do you get?
  24. 24.895? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.16?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 64 and take away the sum of its digits. What do you get?
  27. 27.Take 28 and take away the sum of its digits. What do you get?
  28. 28.82?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.42? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.503? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?339 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.106? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.83?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 90 and take away the sum of its digits. What do you get?
  36. 36.2?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 40 and take away the sum of its digits. What do you get?
  38. 38.?163 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?506 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?150 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. 45
  3. 54
  4. 7
  5. 6
  6. 5
  7. 5
  8. 36
  9. 9
  10. 4
  11. 4
  12. 2
  13. 5
  14. 8
  15. 7
  16. 6
  17. 36
  18. 7
  19. 5
  20. 18
  21. 18
  22. 18
  23. 36
  24. 5
  25. 2
  26. 54
  27. 18
  28. 6
  29. 3
  30. 1
  31. 3
  32. 2
  33. 8
  34. 5
  35. 81
  36. 8
  37. 36
  38. 8
  39. 7
  40. 3

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