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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 559 · 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.?622 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 14 and take away the sum of its digits. What do you get?
  3. 3.21?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?800 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 25 and take away the sum of its digits. What do you get?
  7. 7.?930 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?286 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 55 and take away the sum of its digits. What do you get?
  11. 11.37?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.8?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?878 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 52 and take away the sum of its digits. What do you get?
  15. 15.Take 47 and take away the sum of its digits. What do you get?
  16. 16.?977 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.80?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 63 and take away the sum of its digits. What do you get?
  19. 19.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 27 and take away the sum of its digits. What do you get?
  21. 21.88?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 31 and take away the sum of its digits. What do you get?
  23. 23.5?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.551? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 67 and take away the sum of its digits. What do you get?
  26. 26.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 96 and take away the sum of its digits. What do you get?
  28. 28.Take 50 and take away the sum of its digits. What do you get?
  29. 29.Take 45 and take away the sum of its digits. What do you get?
  30. 30.?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 57 and take away the sum of its digits. What do you get?
  32. 32.Take 43 and take away the sum of its digits. What do you get?
  33. 33.?048 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 64 and take away the sum of its digits. What do you get?
  35. 35.7?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.397? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?983 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?939 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?967 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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