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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 251 · 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. 1.480? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.79?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?287 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.370? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.363? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.5?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 95 and take away the sum of its digits. What do you get?
  9. 9.262? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?002 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.39?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.497? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.2?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?710 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.38? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.3?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.7?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.9?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 55 and take away the sum of its digits. What do you get?
  23. 23.5?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.22?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.1?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 53 and take away the sum of its digits. What do you get?
  27. 27.600? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.858? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 14 and take away the sum of its digits. What do you get?
  30. 30.Take 32 and take away the sum of its digits. What do you get?
  31. 31.Take 29 and take away the sum of its digits. What do you get?
  32. 32.4?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 20 and take away the sum of its digits. What do you get?
  37. 37.83? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 78 and take away the sum of its digits. What do you get?
  39. 39.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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