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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 759 · 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. 1.411? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 39 and take away the sum of its digits. What do you get?
  3. 3.Take 68 and take away the sum of its digits. What do you get?
  4. 4.?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.892? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 76 and take away the sum of its digits. What do you get?
  7. 7.50?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.61? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.2?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.73? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 31 and take away the sum of its digits. What do you get?
  12. 12.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.783? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.414? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 98 and take away the sum of its digits. What do you get?
  16. 16.84?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?210 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?553 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 61 and take away the sum of its digits. What do you get?
  20. 20.15?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 40 and take away the sum of its digits. What do you get?
  22. 22.29? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 55 and take away the sum of its digits. What do you get?
  24. 24.Take 25 and take away the sum of its digits. What do you get?
  25. 25.Take 17 and take away the sum of its digits. What do you get?
  26. 26.Take 57 and take away the sum of its digits. What do you get?
  27. 27.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 53 and take away the sum of its digits. What do you get?
  29. 29.Take 56 and take away the sum of its digits. What do you get?
  30. 30.?386 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.2?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 85 and take away the sum of its digits. What do you get?
  33. 33.Take 38 and take away the sum of its digits. What do you get?
  34. 34.Take 11 and take away the sum of its digits. What do you get?
  35. 35.Take 91 and take away the sum of its digits. What do you get?
  36. 36.6?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 28 and take away the sum of its digits. What do you get?
  38. 38.?878 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 44 and take away the sum of its digits. What do you get?
  40. 40.714? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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