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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 454 · 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 22 and take away the sum of its digits. What do you get?
  2. 2.?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.670? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.80?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?164 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.762? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 90 and take away the sum of its digits. What do you get?
  9. 9.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?454 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.81?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.854? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 75 and take away the sum of its digits. What do you get?
  14. 14.Take 15 and take away the sum of its digits. What do you get?
  15. 15.?781 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 96 and take away the sum of its digits. What do you get?
  17. 17.Take 56 and take away the sum of its digits. What do you get?
  18. 18.46?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.4?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 42 and take away the sum of its digits. What do you get?
  21. 21.?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 62 and take away the sum of its digits. What do you get?
  25. 25.8?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.28?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 33 and take away the sum of its digits. What do you get?
  28. 28.Take 17 and take away the sum of its digits. What do you get?
  29. 29.Take 31 and take away the sum of its digits. What do you get?
  30. 30.Take 91 and take away the sum of its digits. What do you get?
  31. 31.39?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.415? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?361 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 19 and take away the sum of its digits. What do you get?
  37. 37.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 34 and take away the sum of its digits. What do you get?
  39. 39.Take 73 and take away the sum of its digits. What do you get?
  40. 40.30?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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