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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 506 · 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 64 and take away the sum of its digits. What do you get?
  2. 2.7?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.267? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 18 and take away the sum of its digits. What do you get?
  6. 6.543? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 96 and take away the sum of its digits. What do you get?
  8. 8.83? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?003 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.307? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.375? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.48?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.143? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.6?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?835 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 69 and take away the sum of its digits. What do you get?
  17. 17.45?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 20 and take away the sum of its digits. What do you get?
  20. 20.Take 81 and take away the sum of its digits. What do you get?
  21. 21.3?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.2?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 70 and take away the sum of its digits. What do you get?
  24. 24.647? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 36 and take away the sum of its digits. What do you get?
  26. 26.?809 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?969 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 62 and take away the sum of its digits. What do you get?
  29. 29.433? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.3?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?521 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.2?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.68?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.652? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?986 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.494? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?773 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.810? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 54
  2. 5
  3. 3
  4. 8
  5. 9
  6. 6
  7. 81
  8. 7
  9. 6
  10. 8
  11. 3
  12. 4
  13. 1
  14. 2
  15. 2
  16. 54
  17. 7
  18. 9
  19. 18
  20. 72
  21. 8
  22. 8
  23. 63
  24. 1
  25. 27
  26. 1
  27. 3
  28. 54
  29. 8
  30. 2
  31. 1
  32. 8
  33. 8
  34. 5
  35. 4
  36. 1
  37. 6
  38. 1
  39. 9
  40. 9

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