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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 937 · 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. 1.670? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.579? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?439 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?894 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.775? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.614? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 77 and take away the sum of its digits. What do you get?
  10. 10.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 80 and take away the sum of its digits. What do you get?
  12. 12.?173 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.798? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.436? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 19 and take away the sum of its digits. What do you get?
  17. 17.Take 54 and take away the sum of its digits. What do you get?
  18. 18.Take 17 and take away the sum of its digits. What do you get?
  19. 19.Take 96 and take away the sum of its digits. What do you get?
  20. 20.7?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?637 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.65?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?290 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.49?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 50 and take away the sum of its digits. What do you get?
  26. 26.209? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.60?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.5?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.17?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.3?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?537 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.1?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 33 and take away the sum of its digits. What do you get?
  35. 35.Take 86 and take away the sum of its digits. What do you get?
  36. 36.70?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?448 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 93 and take away the sum of its digits. What do you get?
  39. 39.167? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 27 and take away the sum of its digits. What do you get?

Answer key

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

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