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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 837 · 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 36 and take away the sum of its digits. What do you get?
  2. 2.Take 69 and take away the sum of its digits. What do you get?
  3. 3.Take 67 and take away the sum of its digits. What do you get?
  4. 4.?501 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?132 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 24 and take away the sum of its digits. What do you get?
  7. 7.Take 60 and take away the sum of its digits. What do you get?
  8. 8.Take 32 and take away the sum of its digits. What do you get?
  9. 9.Take 81 and take away the sum of its digits. What do you get?
  10. 10.820? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 96 and take away the sum of its digits. What do you get?
  12. 12.2?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 82 and take away the sum of its digits. What do you get?
  14. 14.?760 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.259? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 47 and take away the sum of its digits. What do you get?
  17. 17.2?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.22?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 35 and take away the sum of its digits. What do you get?
  21. 21.691? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.392? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.75?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?811 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?800 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.67?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 25 and take away the sum of its digits. What do you get?
  28. 28.Take 92 and take away the sum of its digits. What do you get?
  29. 29.Take 91 and take away the sum of its digits. What do you get?
  30. 30.190? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?607 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.791? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 80 and take away the sum of its digits. What do you get?
  35. 35.258? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?723 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 40 and take away the sum of its digits. What do you get?
  38. 38.86?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?483 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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