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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 613 · 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. 1.70?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.72?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 15 and take away the sum of its digits. What do you get?
  5. 5.Take 26 and take away the sum of its digits. What do you get?
  6. 6.Take 36 and take away the sum of its digits. What do you get?
  7. 7.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.640? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?554 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.712? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?511 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 66 and take away the sum of its digits. What do you get?
  14. 14.Take 25 and take away the sum of its digits. What do you get?
  15. 15.Take 80 and take away the sum of its digits. What do you get?
  16. 16.14?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 42 and take away the sum of its digits. What do you get?
  18. 18.Take 35 and take away the sum of its digits. What do you get?
  19. 19.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?145 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.622? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?508 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?687 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 12 and take away the sum of its digits. What do you get?
  25. 25.?245 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?988 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 58 and take away the sum of its digits. What do you get?
  28. 28.222? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?767 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 29 and take away the sum of its digits. What do you get?
  31. 31.?277 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.9?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 53 and take away the sum of its digits. What do you get?
  34. 34.58? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 88 and take away the sum of its digits. What do you get?
  36. 36.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?985 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?655 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 14 and take away the sum of its digits. What do you get?
  40. 40.618? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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