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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 906 · 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.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.33? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 25 and take away the sum of its digits. What do you get?
  5. 5.Take 49 and take away the sum of its digits. What do you get?
  6. 6.744? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.4?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.77?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 96 and take away the sum of its digits. What do you get?
  10. 10.8?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 52 and take away the sum of its digits. What do you get?
  12. 12.Take 16 and take away the sum of its digits. What do you get?
  13. 13.Take 11 and take away the sum of its digits. What do you get?
  14. 14.Take 41 and take away the sum of its digits. What do you get?
  15. 15.Take 81 and take away the sum of its digits. What do you get?
  16. 16.81?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?277 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.8?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 21 and take away the sum of its digits. What do you get?
  20. 20.860? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?197 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.3?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 78 and take away the sum of its digits. What do you get?
  25. 25.?248 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.571? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?629 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 91 and take away the sum of its digits. What do you get?
  30. 30.61?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.253? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.100? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 38 and take away the sum of its digits. What do you get?
  34. 34.Take 60 and take away the sum of its digits. What do you get?
  35. 35.Take 17 and take away the sum of its digits. What do you get?
  36. 36.8?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 43 and take away the sum of its digits. What do you get?
  38. 38.Take 86 and take away the sum of its digits. What do you get?
  39. 39.Take 83 and take away the sum of its digits. What do you get?
  40. 40.6?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. 2
  4. 18
  5. 36
  6. 3
  7. 3
  8. 8
  9. 81
  10. 6
  11. 45
  12. 9
  13. 9
  14. 36
  15. 72
  16. 2
  17. 2
  18. 3
  19. 18
  20. 4
  21. 8
  22. 1
  23. 4
  24. 63
  25. 4
  26. 5
  27. 1
  28. 3
  29. 81
  30. 8
  31. 8
  32. 8
  33. 27
  34. 54
  35. 9
  36. 7
  37. 36
  38. 72
  39. 72
  40. 3

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