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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 440 · 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. 1.5?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?060 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.208? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 58 and take away the sum of its digits. What do you get?
  6. 6.Take 38 and take away the sum of its digits. What do you get?
  7. 7.?878 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 36 and take away the sum of its digits. What do you get?
  9. 9.2?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.143? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?705 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 91 and take away the sum of its digits. What do you get?
  13. 13.2?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.813? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.8?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?086 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?136 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.177? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 51 and take away the sum of its digits. What do you get?
  20. 20.599? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?057 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 70 and take away the sum of its digits. What do you get?
  23. 23.606? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 18 and take away the sum of its digits. What do you get?
  25. 25.Take 48 and take away the sum of its digits. What do you get?
  26. 26.Take 66 and take away the sum of its digits. What do you get?
  27. 27.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.126? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 17 and take away the sum of its digits. What do you get?
  30. 30.88?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 30 and take away the sum of its digits. What do you get?
  32. 32.Take 50 and take away the sum of its digits. What do you get?
  33. 33.Take 21 and take away the sum of its digits. What do you get?
  34. 34.Take 52 and take away the sum of its digits. What do you get?
  35. 35.26?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 37 and take away the sum of its digits. What do you get?
  40. 40.56?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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