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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 831 · 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. 1.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?314 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?457 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.4?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.89?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.38?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 32 and take away the sum of its digits. What do you get?
  10. 10.Take 31 and take away the sum of its digits. What do you get?
  11. 11.Take 30 and take away the sum of its digits. What do you get?
  12. 12.23?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.8?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.40?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.405? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.40?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 98 and take away the sum of its digits. What do you get?
  18. 18.Take 36 and take away the sum of its digits. What do you get?
  19. 19.?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.260? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 22 and take away the sum of its digits. What do you get?
  22. 22.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 61 and take away the sum of its digits. What do you get?
  24. 24.Take 97 and take away the sum of its digits. What do you get?
  25. 25.Take 20 and take away the sum of its digits. What do you get?
  26. 26.3?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.75?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.9?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 13 and take away the sum of its digits. What do you get?
  30. 30.Take 64 and take away the sum of its digits. What do you get?
  31. 31.Take 38 and take away the sum of its digits. What do you get?
  32. 32.1?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 50 and take away the sum of its digits. What do you get?
  34. 34.?701 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.56?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.78?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 17 and take away the sum of its digits. What do you get?
  38. 38.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?276 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 72 and take away the sum of its digits. What do you get?

Answer key

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

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