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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 718 · 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. 1.809? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.197? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.36?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?569 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?887 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 52 and take away the sum of its digits. What do you get?
  9. 9.3?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?480 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?874 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?461 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.719? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 61 and take away the sum of its digits. What do you get?
  15. 15.18? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.4?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 17 and take away the sum of its digits. What do you get?
  18. 18.Take 91 and take away the sum of its digits. What do you get?
  19. 19.74?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.559? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.25?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.26?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.54?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.68?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 60 and take away the sum of its digits. What do you get?
  26. 26.Take 18 and take away the sum of its digits. What do you get?
  27. 27.Take 40 and take away the sum of its digits. What do you get?
  28. 28.Take 53 and take away the sum of its digits. What do you get?
  29. 29.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.85? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 57 and take away the sum of its digits. What do you get?
  34. 34.672? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.83?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?248 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.37?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?854 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?698 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.514? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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