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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 648 · 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 32 and take away the sum of its digits. What do you get?
  2. 2.Take 69 and take away the sum of its digits. What do you get?
  3. 3.5?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.7?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 22 and take away the sum of its digits. What do you get?
  6. 6.36?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 15 and take away the sum of its digits. What do you get?
  8. 8.Take 50 and take away the sum of its digits. What do you get?
  9. 9.24?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 30 and take away the sum of its digits. What do you get?
  11. 11.Take 55 and take away the sum of its digits. What do you get?
  12. 12.486? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 68 and take away the sum of its digits. What do you get?
  14. 14.168? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 19 and take away the sum of its digits. What do you get?
  16. 16.Take 54 and take away the sum of its digits. What do you get?
  17. 17.43?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 80 and take away the sum of its digits. What do you get?
  19. 19.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.434? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?076 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.2?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.32?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.564? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.21?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 23 and take away the sum of its digits. What do you get?
  27. 27.61?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 67 and take away the sum of its digits. What do you get?
  29. 29.?440 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.36?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 73 and take away the sum of its digits. What do you get?
  32. 32.?930 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.77? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.757? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 52 and take away the sum of its digits. What do you get?
  37. 37.Take 12 and take away the sum of its digits. What do you get?
  38. 38.Take 91 and take away the sum of its digits. What do you get?
  39. 39.Take 45 and take away the sum of its digits. What do you get?
  40. 40.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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