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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 241 · 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.Take 93 and take away the sum of its digits. What do you get?
  2. 2.2?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.208? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 57 and take away the sum of its digits. What do you get?
  5. 5.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?514 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 79 and take away the sum of its digits. What do you get?
  8. 8.Take 46 and take away the sum of its digits. What do you get?
  9. 9.76?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.330? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.10?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 32 and take away the sum of its digits. What do you get?
  14. 14.?951 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 62 and take away the sum of its digits. What do you get?
  16. 16.?436 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?659 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 60 and take away the sum of its digits. What do you get?
  20. 20.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?383 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.52?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.37? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.387? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.17?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?575 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.74?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.62?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 21 and take away the sum of its digits. What do you get?
  30. 30.5?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 52 and take away the sum of its digits. What do you get?
  32. 32.26?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?743 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.56?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.74?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 66 and take away the sum of its digits. What do you get?
  38. 38.?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.5?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 86 and take away the sum of its digits. What do you get?

Answer key

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

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