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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 272 · 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. 1.24?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?561 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.47?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.719? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 20 and take away the sum of its digits. What do you get?
  6. 6.Take 44 and take away the sum of its digits. What do you get?
  7. 7.?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.66?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 25 and take away the sum of its digits. What do you get?
  10. 10.8?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.55?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.13?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 15 and take away the sum of its digits. What do you get?
  14. 14.?708 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.80?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 70 and take away the sum of its digits. What do you get?
  17. 17.1?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.5?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.39? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 43 and take away the sum of its digits. What do you get?
  23. 23.10?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 87 and take away the sum of its digits. What do you get?
  25. 25.3?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.42?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.300? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.46?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.272? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.47?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 86 and take away the sum of its digits. What do you get?
  32. 32.550? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.60?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?896 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 89 and take away the sum of its digits. What do you get?
  36. 36.Take 32 and take away the sum of its digits. What do you get?
  37. 37.6?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 67 and take away the sum of its digits. What do you get?
  39. 39.?181 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?359 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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