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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 75 · 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.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.8?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.3?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 58 and take away the sum of its digits. What do you get?
  8. 8.Take 92 and take away the sum of its digits. What do you get?
  9. 9.Take 17 and take away the sum of its digits. What do you get?
  10. 10.93? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?776 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 63 and take away the sum of its digits. What do you get?
  13. 13.80?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.873? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 19 and take away the sum of its digits. What do you get?
  16. 16.352? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.567? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.624? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.29?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.877? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.459? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 68 and take away the sum of its digits. What do you get?
  24. 24.281? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?233 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 27 and take away the sum of its digits. What do you get?
  27. 27.608? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.614? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?337 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.399? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 15 and take away the sum of its digits. What do you get?
  32. 32.78?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 51 and take away the sum of its digits. What do you get?
  34. 34.756? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 47 and take away the sum of its digits. What do you get?
  36. 36.Take 90 and take away the sum of its digits. What do you get?
  37. 37.56?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 89 and take away the sum of its digits. What do you get?
  39. 39.46?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 43 and take away the sum of its digits. What do you get?

Answer key

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

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