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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 609 · 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.?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.311? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.71?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.300? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?075 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 70 and take away the sum of its digits. What do you get?
  7. 7.?196 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?869 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?038 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.42?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 58 and take away the sum of its digits. What do you get?
  12. 12.6?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?889 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 84 and take away the sum of its digits. What do you get?
  15. 15.Take 29 and take away the sum of its digits. What do you get?
  16. 16.68?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?878 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 85 and take away the sum of its digits. What do you get?
  20. 20.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 25 and take away the sum of its digits. What do you get?
  22. 22.Take 12 and take away the sum of its digits. What do you get?
  23. 23.1?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.47?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?190 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.110? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 65 and take away the sum of its digits. What do you get?
  28. 28.731? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?958 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.30?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.6?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.790? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.440? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 55 and take away the sum of its digits. What do you get?
  37. 37.538? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?113 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.5?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 77 and take away the sum of its digits. What do you get?

Answer key

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

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