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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 893 · 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.Take 84 and take away the sum of its digits. What do you get?
  2. 2.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 65 and take away the sum of its digits. What do you get?
  4. 4.7?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 94 and take away the sum of its digits. What do you get?
  6. 6.3?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 85 and take away the sum of its digits. What do you get?
  9. 9.Take 26 and take away the sum of its digits. What do you get?
  10. 10.Take 95 and take away the sum of its digits. What do you get?
  11. 11.3?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?240 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.4?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.46?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.813? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?022 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.30?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.3?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 27 and take away the sum of its digits. What do you get?
  20. 20.Take 59 and take away the sum of its digits. What do you get?
  21. 21.106? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 92 and take away the sum of its digits. What do you get?
  23. 23.Take 66 and take away the sum of its digits. What do you get?
  24. 24.?716 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.394? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?683 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.1?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?723 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 47 and take away the sum of its digits. What do you get?
  31. 31.400? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 29 and take away the sum of its digits. What do you get?
  33. 33.Take 18 and take away the sum of its digits. What do you get?
  34. 34.3?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.305? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.4?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.457? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.9?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.320? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 15 and take away the sum of its digits. What do you get?

Answer key

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

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