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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 188 · 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. 1.35?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.2?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.2?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.69?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.7?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?452 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.41?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?668 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.48?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 29 and take away the sum of its digits. What do you get?
  13. 13.7?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.225? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?672 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 87 and take away the sum of its digits. What do you get?
  18. 18.824? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?856 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.805? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 46 and take away the sum of its digits. What do you get?
  22. 22.?709 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.634? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.54?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.75?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.6?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.777? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.173? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?384 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.844? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.20?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 34 and take away the sum of its digits. What do you get?
  36. 36.166? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.7?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.7?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 47 and take away the sum of its digits. What do you get?
  40. 40.Take 41 and take away the sum of its digits. What do you get?

Answer key

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

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