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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 697 · 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. 1.87?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.5?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?700 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 77 and take away the sum of its digits. What do you get?
  6. 6.Take 73 and take away the sum of its digits. What do you get?
  7. 7.107? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.570? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 76 and take away the sum of its digits. What do you get?
  10. 10.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 70 and take away the sum of its digits. What do you get?
  12. 12.52?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.3?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 45 and take away the sum of its digits. What do you get?
  15. 15.46?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 67 and take away the sum of its digits. What do you get?
  17. 17.330? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.43?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 26 and take away the sum of its digits. What do you get?
  20. 20.4?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.630? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 80 and take away the sum of its digits. What do you get?
  23. 23.?497 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 69 and take away the sum of its digits. What do you get?
  25. 25.6?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 98 and take away the sum of its digits. What do you get?
  27. 27.510? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 75 and take away the sum of its digits. What do you get?
  29. 29.?624 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.746? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.728? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.896? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.2?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.172? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 52 and take away the sum of its digits. What do you get?
  39. 39.10?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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