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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 484 · 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.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.47?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.6?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?620 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 16 and take away the sum of its digits. What do you get?
  8. 8.17?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.40?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?644 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.3?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 61 and take away the sum of its digits. What do you get?
  14. 14.7?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.347? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 14 and take away the sum of its digits. What do you get?
  17. 17.233? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.372? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.312? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 40 and take away the sum of its digits. What do you get?
  22. 22.3?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?260 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 17 and take away the sum of its digits. What do you get?
  26. 26.6?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?949 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.1?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 79 and take away the sum of its digits. What do you get?
  31. 31.Take 53 and take away the sum of its digits. What do you get?
  32. 32.383? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 94 and take away the sum of its digits. What do you get?
  34. 34.?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.88?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.539? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.4?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?484 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 78 and take away the sum of its digits. What do you get?
  40. 40.?607 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. 3
  3. 4
  4. 3
  5. 7
  6. 1
  7. 9
  8. 6
  9. 1
  10. 4
  11. 3
  12. 8
  13. 54
  14. 8
  15. 4
  16. 9
  17. 1
  18. 3
  19. 6
  20. 3
  21. 36
  22. 8
  23. 1
  24. 3
  25. 9
  26. 3
  27. 9
  28. 5
  29. 2
  30. 63
  31. 45
  32. 4
  33. 81
  34. 3
  35. 5
  36. 1
  37. 2
  38. 2
  39. 63
  40. 5

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