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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 705 · 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 62 and take away the sum of its digits. What do you get?
  2. 2.87? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.263? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 74 and take away the sum of its digits. What do you get?
  5. 5.420? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?017 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.47?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 47 and take away the sum of its digits. What do you get?
  9. 9.1?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?359 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.30?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?874 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.208? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 85 and take away the sum of its digits. What do you get?
  16. 16.Take 77 and take away the sum of its digits. What do you get?
  17. 17.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 60 and take away the sum of its digits. What do you get?
  19. 19.?449 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 24 and take away the sum of its digits. What do you get?
  21. 21.127? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 48 and take away the sum of its digits. What do you get?
  23. 23.Take 67 and take away the sum of its digits. What do you get?
  24. 24.Take 17 and take away the sum of its digits. What do you get?
  25. 25.Take 36 and take away the sum of its digits. What do you get?
  26. 26.Take 80 and take away the sum of its digits. What do you get?
  27. 27.23?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?316 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.5?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.587? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?813 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 11 and take away the sum of its digits. What do you get?
  33. 33.70?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?971 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?085 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.4?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.5?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 15 and take away the sum of its digits. What do you get?
  39. 39.617? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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