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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 665 · 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 63 and take away the sum of its digits. What do you get?
  2. 2.?230 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?304 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.840? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 67 and take away the sum of its digits. What do you get?
  7. 7.Take 31 and take away the sum of its digits. What do you get?
  8. 8.?527 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 32 and take away the sum of its digits. What do you get?
  11. 11.15?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 87 and take away the sum of its digits. What do you get?
  13. 13.Take 85 and take away the sum of its digits. What do you get?
  14. 14.36?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?707 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?277 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 71 and take away the sum of its digits. What do you get?
  19. 19.3?30 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.?922 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?424 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.49?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.88? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.137? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 19 and take away the sum of its digits. What do you get?
  29. 29.556? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.4?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 52 and take away the sum of its digits. What do you get?
  32. 32.Take 69 and take away the sum of its digits. What do you get?
  33. 33.Take 65 and take away the sum of its digits. What do you get?
  34. 34.543? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.48?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 99 and take away the sum of its digits. What do you get?
  37. 37.Take 81 and take away the sum of its digits. What do you get?
  38. 38.6?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.71?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 29 and take away the sum of its digits. What do you get?

Answer key

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

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