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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 812 · 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. 1.23?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 16 and take away the sum of its digits. What do you get?
  3. 3.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.208? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.7?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 66 and take away the sum of its digits. What do you get?
  7. 7.793? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.64?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 49 and take away the sum of its digits. What do you get?
  10. 10.396? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.503? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.8?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 29 and take away the sum of its digits. What do you get?
  14. 14.885? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 38 and take away the sum of its digits. What do you get?
  16. 16.1?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.35?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.54?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 68 and take away the sum of its digits. What do you get?
  20. 20.11?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?921 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 22 and take away the sum of its digits. What do you get?
  24. 24.3?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.139? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 83 and take away the sum of its digits. What do you get?
  27. 27.666? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.323? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.86?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 21 and take away the sum of its digits. What do you get?
  31. 31.32?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.3?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 43 and take away the sum of its digits. What do you get?
  35. 35.Take 73 and take away the sum of its digits. What do you get?
  36. 36.75?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.737? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.207? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.19?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.73?7 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. 9
  3. 8
  4. 8
  5. 5
  6. 54
  7. 8
  8. 9
  9. 36
  10. 9
  11. 1
  12. 3
  13. 18
  14. 6
  15. 27
  16. 1
  17. 1
  18. 2
  19. 54
  20. 6
  21. 6
  22. 1
  23. 18
  24. 6
  25. 5
  26. 72
  27. 9
  28. 1
  29. 9
  30. 18
  31. 9
  32. 9
  33. 3
  34. 36
  35. 63
  36. 1
  37. 1
  38. 9
  39. 3
  40. 1

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