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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 704 · 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 52 and take away the sum of its digits. What do you get?
  2. 2.Take 72 and take away the sum of its digits. What do you get?
  3. 3.323? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?735 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?683 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.44? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.8?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?145 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?760 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.35?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 84 and take away the sum of its digits. What do you get?
  12. 12.Take 89 and take away the sum of its digits. What do you get?
  13. 13.5?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.64?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?525 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 93 and take away the sum of its digits. What do you get?
  18. 18.Take 20 and take away the sum of its digits. What do you get?
  19. 19.3?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 32 and take away the sum of its digits. What do you get?
  21. 21.Take 92 and take away the sum of its digits. What do you get?
  22. 22.Take 57 and take away the sum of its digits. What do you get?
  23. 23.18?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.341? 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. 26.83?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 18 and take away the sum of its digits. What do you get?
  28. 28.Take 82 and take away the sum of its digits. What do you get?
  29. 29.?221 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 46 and take away the sum of its digits. What do you get?
  31. 31.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.704? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?437 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.290? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.250? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?069 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.813? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.289? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.42?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 85 and take away the sum of its digits. What do you get?

Answer key

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

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