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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 106 · 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.?921 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 75 and take away the sum of its digits. What do you get?
  3. 3.Take 81 and take away the sum of its digits. What do you get?
  4. 4.22?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.1?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 15 and take away the sum of its digits. What do you get?
  9. 9.39?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.88?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?392 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 50 and take away the sum of its digits. What do you get?
  13. 13.Take 18 and take away the sum of its digits. What do you get?
  14. 14.Take 32 and take away the sum of its digits. What do you get?
  15. 15.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.34?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 27 and take away the sum of its digits. What do you get?
  18. 18.Take 16 and take away the sum of its digits. What do you get?
  19. 19.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 85 and take away the sum of its digits. What do you get?
  21. 21.7?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?897 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?667 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?647 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 61 and take away the sum of its digits. What do you get?
  28. 28.503? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?600 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?654 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 33 and take away the sum of its digits. What do you get?
  32. 32.85?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?208 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 90 and take away the sum of its digits. What do you get?
  36. 36.404? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?411 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 54 and take away the sum of its digits. What do you get?
  39. 39.?489 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?015 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. 63
  3. 72
  4. 1
  5. 7
  6. 9
  7. 5
  8. 9
  9. 8
  10. 7
  11. 4
  12. 45
  13. 9
  14. 27
  15. 6
  16. 9
  17. 18
  18. 9
  19. 2
  20. 72
  21. 2
  22. 3
  23. 3
  24. 8
  25. 1
  26. 8
  27. 54
  28. 1
  29. 3
  30. 3
  31. 27
  32. 4
  33. 8
  34. 4
  35. 81
  36. 1
  37. 3
  38. 45
  39. 6
  40. 3

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