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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 713 · 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. 1.7?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 13 and take away the sum of its digits. What do you get?
  3. 3.1?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.9?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.391? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 97 and take away the sum of its digits. What do you get?
  7. 7.Take 21 and take away the sum of its digits. What do you get?
  8. 8.812? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 39 and take away the sum of its digits. What do you get?
  10. 10.Take 66 and take away the sum of its digits. What do you get?
  11. 11.?950 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 65 and take away the sum of its digits. What do you get?
  13. 13.57?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?100 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.158? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.76?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?479 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.666? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.640? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.84?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 51 and take away the sum of its digits. What do you get?
  23. 23.759? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?336 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 83 and take away the sum of its digits. What do you get?
  27. 27.Take 27 and take away the sum of its digits. What do you get?
  28. 28.Take 53 and take away the sum of its digits. What do you get?
  29. 29.1?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.562? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.341? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.677? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?985 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.5?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?096 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 36 and take away the sum of its digits. What do you get?
  39. 39.79?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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