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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 898 · 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?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.59?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?977 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.12?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 75 and take away the sum of its digits. What do you get?
  6. 6.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 58 and take away the sum of its digits. What do you get?
  8. 8.Take 50 and take away the sum of its digits. What do you get?
  9. 9.1?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 63 and take away the sum of its digits. What do you get?
  11. 11.50?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?204 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?598 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.71?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.6?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?132 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.898? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 98 and take away the sum of its digits. What do you get?
  21. 21.3?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 35 and take away the sum of its digits. What do you get?
  23. 23.717? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.813? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 25 and take away the sum of its digits. What do you get?
  26. 26.Take 80 and take away the sum of its digits. What do you get?
  27. 27.Take 20 and take away the sum of its digits. What do you get?
  28. 28.Take 76 and take away the sum of its digits. What do you get?
  29. 29.?260 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.304? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 16 and take away the sum of its digits. What do you get?
  32. 32.255? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.296? 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. 35.542? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.7?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.573? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 28 and take away the sum of its digits. What do you get?
  39. 39.Take 67 and take away the sum of its digits. What do you get?
  40. 40.666? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 5
  3. 4
  4. 4
  5. 63
  6. 8
  7. 45
  8. 45
  9. 7
  10. 54
  11. 7
  12. 3
  13. 3
  14. 5
  15. 8
  16. 9
  17. 4
  18. 3
  19. 2
  20. 81
  21. 5
  22. 27
  23. 3
  24. 6
  25. 18
  26. 72
  27. 18
  28. 63
  29. 1
  30. 2
  31. 9
  32. 6
  33. 1
  34. 36
  35. 7
  36. 2
  37. 3
  38. 18
  39. 54
  40. 9

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