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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 174 · 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. 1.44?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?881 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?770 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.4?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 82 and take away the sum of its digits. What do you get?
  6. 6.?975 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.39?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?190 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.372? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?074 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.74?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?662 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.6?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.341? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 36 and take away the sum of its digits. What do you get?
  17. 17.Take 43 and take away the sum of its digits. What do you get?
  18. 18.Take 12 and take away the sum of its digits. What do you get?
  19. 19.17?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.398? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.47?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 42 and take away the sum of its digits. What do you get?
  23. 23.7?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?084 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.830? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 67 and take away the sum of its digits. What do you get?
  29. 29.3?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 68 and take away the sum of its digits. What do you get?
  31. 31.?055 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.35?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 96 and take away the sum of its digits. What do you get?
  35. 35.1?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 56 and take away the sum of its digits. What do you get?
  37. 37.73?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.27?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 51 and take away the sum of its digits. What do you get?
  40. 40.86?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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