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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 783 · 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 37 and take away the sum of its digits. What do you get?
  2. 2.?012 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.374? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?424 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 72 and take away the sum of its digits. What do you get?
  7. 7.?034 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?911 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.429? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 70 and take away the sum of its digits. What do you get?
  11. 11.Take 82 and take away the sum of its digits. What do you get?
  12. 12.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.2?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 69 and take away the sum of its digits. What do you get?
  15. 15.?078 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 53 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.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.43?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.85?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 14 and take away the sum of its digits. What do you get?
  23. 23.100? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.785? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.4?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.402? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?047 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 26 and take away the sum of its digits. What do you get?
  29. 29.1?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 85 and take away the sum of its digits. What do you get?
  31. 31.284? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.51?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 61 and take away the sum of its digits. What do you get?
  35. 35.?780 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 99 and take away the sum of its digits. What do you get?
  37. 37.Take 96 and take away the sum of its digits. What do you get?
  38. 38.Take 39 and take away the sum of its digits. What do you get?
  39. 39.5?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?87 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. 6
  3. 4
  4. 3
  5. 8
  6. 63
  7. 2
  8. 7
  9. 3
  10. 63
  11. 72
  12. 5
  13. 9
  14. 54
  15. 3
  16. 45
  17. 45
  18. 7
  19. 8
  20. 3
  21. 1
  22. 9
  23. 8
  24. 7
  25. 3
  26. 3
  27. 7
  28. 18
  29. 3
  30. 72
  31. 4
  32. 5
  33. 8
  34. 54
  35. 3
  36. 81
  37. 81
  38. 27
  39. 3
  40. 6

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