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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 540 · 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.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?836 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.244? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.5?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 11 and take away the sum of its digits. What do you get?
  7. 7.Take 27 and take away the sum of its digits. What do you get?
  8. 8.4?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 46 and take away the sum of its digits. What do you get?
  10. 10.7?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.610? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.20?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 76 and take away the sum of its digits. What do you get?
  14. 14.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.17?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.705? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?062 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.292? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.77?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.40?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.88?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.8?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 66 and take away the sum of its digits. What do you get?
  27. 27.14?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?446 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.3?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.875? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.19?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 82 and take away the sum of its digits. What do you get?
  33. 33.767? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?436 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 83 and take away the sum of its digits. What do you get?
  37. 37.39? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.1?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 51 and take away the sum of its digits. What do you get?
  40. 40.?206 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. 1
  3. 1
  4. 8
  5. 3
  6. 9
  7. 18
  8. 2
  9. 36
  10. 5
  11. 2
  12. 7
  13. 63
  14. 3
  15. 6
  16. 6
  17. 1
  18. 5
  19. 8
  20. 7
  21. 5
  22. 1
  23. 7
  24. 9
  25. 6
  26. 54
  27. 1
  28. 4
  29. 4
  30. 7
  31. 1
  32. 72
  33. 7
  34. 3
  35. 5
  36. 72
  37. 6
  38. 7
  39. 45
  40. 1

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