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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 564 · 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 24 and take away the sum of its digits. What do you get?
  2. 2.16? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.20?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.447? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?755 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?376 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 56 and take away the sum of its digits. What do you get?
  8. 8.?201 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 36 and take away the sum of its digits. What do you get?
  10. 10.3?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?631 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.2?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 74 and take away the sum of its digits. What do you get?
  14. 14.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.3?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 43 and take away the sum of its digits. What do you get?
  18. 18.Take 98 and take away the sum of its digits. What do you get?
  19. 19.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?464 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.373? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.6?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?601 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 25 and take away the sum of its digits. What do you get?
  28. 28.?347 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 78 and take away the sum of its digits. What do you get?
  30. 30.Take 29 and take away the sum of its digits. What do you get?
  31. 31.5?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 34 and take away the sum of its digits. What do you get?
  34. 34.Take 66 and take away the sum of its digits. What do you get?
  35. 35.Take 87 and take away the sum of its digits. What do you get?
  36. 36.?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 11 and take away the sum of its digits. What do you get?
  38. 38.318? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 19 and take away the sum of its digits. What do you get?
  40. 40.Take 18 and take away the sum of its digits. What do you get?

Answer key

  1. 18
  2. 2
  3. 1
  4. 3
  5. 1
  6. 2
  7. 45
  8. 6
  9. 27
  10. 7
  11. 8
  12. 7
  13. 63
  14. 9
  15. 2
  16. 2
  17. 36
  18. 81
  19. 2
  20. 4
  21. 2
  22. 5
  23. 2
  24. 1
  25. 2
  26. 1
  27. 18
  28. 4
  29. 63
  30. 18
  31. 8
  32. 4
  33. 27
  34. 54
  35. 72
  36. 2
  37. 9
  38. 6
  39. 9
  40. 9

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