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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 741 · 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 92 and take away the sum of its digits. What do you get?
  2. 2.Take 82 and take away the sum of its digits. What do you get?
  3. 3.?479 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 97 and take away the sum of its digits. What do you get?
  5. 5.Take 96 and take away the sum of its digits. What do you get?
  6. 6.408? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.41?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?031 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.45?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 52 and take away the sum of its digits. What do you get?
  11. 11.58?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 81 and take away the sum of its digits. What do you get?
  14. 14.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 18 and take away the sum of its digits. What do you get?
  16. 16.Take 41 and take away the sum of its digits. What do you get?
  17. 17.8?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 25 and take away the sum of its digits. What do you get?
  19. 19.Take 46 and take away the sum of its digits. What do you get?
  20. 20.20? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 86 and take away the sum of its digits. What do you get?
  22. 22.1?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.25?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?228 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 59 and take away the sum of its digits. What do you get?
  26. 26.629? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?056 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.58?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 64 and take away the sum of its digits. What do you get?
  30. 30.7?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 36 and take away the sum of its digits. What do you get?
  32. 32.Take 93 and take away the sum of its digits. What do you get?
  33. 33.?087 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 69 and take away the sum of its digits. What do you get?
  35. 35.?024 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.1?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?532 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?870 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.467? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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