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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 236 · 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. 1.54?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 41 and take away the sum of its digits. What do you get?
  3. 3.Take 91 and take away the sum of its digits. What do you get?
  4. 4.Take 87 and take away the sum of its digits. What do you get?
  5. 5.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.21?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?768 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?161 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?879 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.879? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.75?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.7?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.136? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?003 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.103? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 25 and take away the sum of its digits. What do you get?
  17. 17.Take 97 and take away the sum of its digits. What do you get?
  18. 18.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 50 and take away the sum of its digits. What do you get?
  20. 20.17?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 23 and take away the sum of its digits. What do you get?
  22. 22.?763 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 18 and take away the sum of its digits. What do you get?
  24. 24.?399 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 58 and take away the sum of its digits. What do you get?
  26. 26.?670 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.14?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 47 and take away the sum of its digits. What do you get?
  30. 30.?087 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.18?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.53? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?569 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 43 and take away the sum of its digits. What do you get?
  35. 35.Take 26 and take away the sum of its digits. What do you get?
  36. 36.?218 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 67 and take away the sum of its digits. What do you get?
  38. 38.723? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?092 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.12?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 5
  2. 36
  3. 81
  4. 72
  5. 8
  6. 5
  7. 6
  8. 1
  9. 3
  10. 3
  11. 6
  12. 5
  13. 8
  14. 6
  15. 5
  16. 18
  17. 81
  18. 1
  19. 45
  20. 3
  21. 18
  22. 2
  23. 9
  24. 6
  25. 45
  26. 5
  27. 3
  28. 9
  29. 36
  30. 3
  31. 2
  32. 1
  33. 7
  34. 36
  35. 18
  36. 7
  37. 54
  38. 6
  39. 7
  40. 8

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