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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 838 · 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. 1.14?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.26?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.132? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 16 and take away the sum of its digits. What do you get?
  5. 5.Take 72 and take away the sum of its digits. What do you get?
  6. 6.Take 76 and take away the sum of its digits. What do you get?
  7. 7.?861 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?959 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.226? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.199? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 81 and take away the sum of its digits. What do you get?
  12. 12.Take 32 and take away the sum of its digits. What do you get?
  13. 13.Take 48 and take away the sum of its digits. What do you get?
  14. 14.25?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.6?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?255 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?031 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?294 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?553 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.98? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 57 and take away the sum of its digits. What do you get?
  23. 23.?511 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.41?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.48?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 80 and take away the sum of its digits. What do you get?
  27. 27.?685 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.123? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?148 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.86? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 86 and take away the sum of its digits. What do you get?
  34. 34.6?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.89?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.731? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?772 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 35 and take away the sum of its digits. What do you get?
  39. 39.Take 22 and take away the sum of its digits. What do you get?
  40. 40.16?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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