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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 734 · 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. 1.65?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.1?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?334 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 27 and take away the sum of its digits. What do you get?
  5. 5.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?484 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?382 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.805? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.25?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.248? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 94 and take away the sum of its digits. What do you get?
  12. 12.Take 33 and take away the sum of its digits. What do you get?
  13. 13.Take 99 and take away the sum of its digits. What do you get?
  14. 14.Take 37 and take away the sum of its digits. What do you get?
  15. 15.?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.7?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 22 and take away the sum of its digits. What do you get?
  18. 18.89?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?350 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 26 and take away the sum of its digits. What do you get?
  21. 21.39?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 16 and take away the sum of its digits. What do you get?
  23. 23.1?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 23 and take away the sum of its digits. What do you get?
  25. 25.?083 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.97? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?456 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 15 and take away the sum of its digits. What do you get?
  30. 30.507? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?304 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 84 and take away the sum of its digits. What do you get?
  33. 33.Take 67 and take away the sum of its digits. What do you get?
  34. 34.?742 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 34 and take away the sum of its digits. What do you get?
  36. 36.?422 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 70 and take away the sum of its digits. What do you get?
  38. 38.4?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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