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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 739 · 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. 1.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.5?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?349 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.1?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.3?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 72 and take away the sum of its digits. What do you get?
  10. 10.5?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 20 and take away the sum of its digits. What do you get?
  12. 12.Take 39 and take away the sum of its digits. What do you get?
  13. 13.230? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?448 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.3?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.306? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?329 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 67 and take away the sum of its digits. What do you get?
  20. 20.538? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.13?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 68 and take away the sum of its digits. What do you get?
  23. 23.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?406 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?919 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.4?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.3?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 84 and take away the sum of its digits. What do you get?
  29. 29.Take 51 and take away the sum of its digits. What do you get?
  30. 30.1?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 85 and take away the sum of its digits. What do you get?
  33. 33.?240 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.681? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.646? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?732 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?051 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 28 and take away the sum of its digits. What do you get?

Answer key

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

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