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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 257 · 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 93 and take away the sum of its digits. What do you get?
  2. 2.Take 81 and take away the sum of its digits. What do you get?
  3. 3.Take 90 and take away the sum of its digits. What do you get?
  4. 4.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 68 and take away the sum of its digits. What do you get?
  6. 6.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 55 and take away the sum of its digits. What do you get?
  8. 8.?579 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.3?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 94 and take away the sum of its digits. What do you get?
  12. 12.Take 75 and take away the sum of its digits. What do you get?
  13. 13.219? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.10?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.9?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 64 and take away the sum of its digits. What do you get?
  18. 18.Take 31 and take away the sum of its digits. What do you get?
  19. 19.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.46?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.72?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 65 and take away the sum of its digits. What do you get?
  24. 24.Take 97 and take away the sum of its digits. What do you get?
  25. 25.25?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?607 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 27 and take away the sum of its digits. What do you get?
  29. 29.Take 44 and take away the sum of its digits. What do you get?
  30. 30.?280 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.653? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.474? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?411 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 35 and take away the sum of its digits. What do you get?
  36. 36.1?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.46?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?663 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.1?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 72 and take away the sum of its digits. What do you get?

Answer key

  1. 81
  2. 72
  3. 81
  4. 1
  5. 54
  6. 8
  7. 45
  8. 6
  9. 6
  10. 2
  11. 81
  12. 63
  13. 6
  14. 5
  15. 5
  16. 3
  17. 54
  18. 27
  19. 6
  20. 4
  21. 1
  22. 5
  23. 54
  24. 81
  25. 9
  26. 5
  27. 9
  28. 18
  29. 36
  30. 8
  31. 4
  32. 8
  33. 3
  34. 3
  35. 27
  36. 9
  37. 3
  38. 3
  39. 7
  40. 63

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