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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 560 · 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.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?775 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.4?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 38 and take away the sum of its digits. What do you get?
  5. 5.719? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 93 and take away the sum of its digits. What do you get?
  7. 7.47?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 80 and take away the sum of its digits. What do you get?
  9. 9.?376 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.608? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.279? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.93? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.178? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.51?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?496 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.3?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 27 and take away the sum of its digits. What do you get?
  23. 23.Take 97 and take away the sum of its digits. What do you get?
  24. 24.Take 88 and take away the sum of its digits. What do you get?
  25. 25.Take 74 and take away the sum of its digits. What do you get?
  26. 26.4?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.73?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 65 and take away the sum of its digits. What do you get?
  29. 29.113? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.30?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?797 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?265 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 13 and take away the sum of its digits. What do you get?
  35. 35.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 43 and take away the sum of its digits. What do you get?
  37. 37.Take 24 and take away the sum of its digits. What do you get?
  38. 38.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?401 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 75 and take away the sum of its digits. What do you get?

Answer key

  1. 7
  2. 8
  3. 8
  4. 27
  5. 1
  6. 81
  7. 4
  8. 72
  9. 2
  10. 4
  11. 9
  12. 9
  13. 6
  14. 7
  15. 2
  16. 8
  17. 1
  18. 4
  19. 8
  20. 2
  21. 1
  22. 18
  23. 81
  24. 72
  25. 63
  26. 9
  27. 8
  28. 54
  29. 4
  30. 4
  31. 4
  32. 5
  33. 2
  34. 9
  35. 9
  36. 36
  37. 18
  38. 2
  39. 4
  40. 63

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