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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 347 · 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.?125 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 98 and take away the sum of its digits. What do you get?
  3. 3.207? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 65 and take away the sum of its digits. What do you get?
  5. 5.Take 77 and take away the sum of its digits. What do you get?
  6. 6.?718 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?614 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?187 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 76 and take away the sum of its digits. What do you get?
  10. 10.?842 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 44 and take away the sum of its digits. What do you get?
  12. 12.5?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.39?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.739? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.178? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.56?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.45?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.57?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?452 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.30?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?078 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.74? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.68?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 33 and take away the sum of its digits. What do you get?
  25. 25.?537 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.73?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 82 and take away the sum of its digits. What do you get?
  28. 28.Take 91 and take away the sum of its digits. What do you get?
  29. 29.?276 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?832 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 18 and take away the sum of its digits. What do you get?
  32. 32.Take 19 and take away the sum of its digits. What do you get?
  33. 33.7?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 97 and take away the sum of its digits. What do you get?
  37. 37.476? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 94 and take away the sum of its digits. What do you get?
  39. 39.4?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 75 and take away the sum of its digits. What do you get?

Answer key

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

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