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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 823 · 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.?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 36 and take away the sum of its digits. What do you get?
  3. 3.?637 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 13 and take away the sum of its digits. What do you get?
  5. 5.4?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 85 and take away the sum of its digits. What do you get?
  7. 7.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?731 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?539 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 44 and take away the sum of its digits. What do you get?
  11. 11.?005 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 84 and take away the sum of its digits. What do you get?
  13. 13.Take 72 and take away the sum of its digits. What do you get?
  14. 14.67?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 59 and take away the sum of its digits. What do you get?
  16. 16.4?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.1?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?670 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 89 and take away the sum of its digits. What do you get?
  21. 21.2?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?825 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.15?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.57?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.38?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.737? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?530 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.42?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?329 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 92 and take away the sum of its digits. What do you get?
  32. 32.4?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.53?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.426? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?781 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?773 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?849 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 97 and take away the sum of its digits. What do you get?
  39. 39.?921 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 24 and take away the sum of its digits. What do you get?

Answer key

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

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