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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 707 · 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 34 and take away the sum of its digits. What do you get?
  2. 2.19?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 65 and take away the sum of its digits. What do you get?
  4. 4.Take 23 and take away the sum of its digits. What do you get?
  5. 5.Take 58 and take away the sum of its digits. What do you get?
  6. 6.Take 13 and take away the sum of its digits. What do you get?
  7. 7.519? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 21 and take away the sum of its digits. What do you get?
  11. 11.Take 44 and take away the sum of its digits. What do you get?
  12. 12.Take 38 and take away the sum of its digits. What do you get?
  13. 13.335? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  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.Take 22 and take away the sum of its digits. What do you get?
  16. 16.832? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.373? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.150? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.4?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?840 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?191 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?641 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.86?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.790? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.66?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.87?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.32?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.4?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 35 and take away the sum of its digits. What do you get?
  34. 34.Take 48 and take away the sum of its digits. What do you get?
  35. 35.?211 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 89 and take away the sum of its digits. What do you get?
  37. 37.?106 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 50 and take away the sum of its digits. What do you get?
  39. 39.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.180? 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. 5
  3. 54
  4. 18
  5. 45
  6. 9
  7. 3
  8. 4
  9. 6
  10. 18
  11. 36
  12. 27
  13. 7
  14. 5
  15. 18
  16. 5
  17. 8
  18. 5
  19. 3
  20. 3
  21. 9
  22. 6
  23. 7
  24. 7
  25. 4
  26. 1
  27. 1
  28. 2
  29. 8
  30. 4
  31. 2
  32. 2
  33. 27
  34. 36
  35. 5
  36. 72
  37. 2
  38. 45
  39. 7
  40. 9

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