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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 255 · 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. 1.8?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 54 and take away the sum of its digits. What do you get?
  3. 3.Take 65 and take away the sum of its digits. What do you get?
  4. 4.33?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.76?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.2?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 31 and take away the sum of its digits. What do you get?
  8. 8.22?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 11 and take away the sum of its digits. What do you get?
  10. 10.21?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 32 and take away the sum of its digits. What do you get?
  12. 12.Take 74 and take away the sum of its digits. What do you get?
  13. 13.Take 20 and take away the sum of its digits. What do you get?
  14. 14.Take 37 and take away the sum of its digits. What do you get?
  15. 15.1?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.85?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 47 and take away the sum of its digits. What do you get?
  19. 19.4?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?545 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.9?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.5?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 13 and take away the sum of its digits. What do you get?
  28. 28.695? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.78?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.257? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.13? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.51?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.23? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 38 and take away the sum of its digits. What do you get?
  36. 36.26?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 36 and take away the sum of its digits. What do you get?
  38. 38.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 30 and take away the sum of its digits. What do you get?
  40. 40.5?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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