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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 700 · 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 64 and take away the sum of its digits. What do you get?
  2. 2.Take 78 and take away the sum of its digits. What do you get?
  3. 3.Take 47 and take away the sum of its digits. What do you get?
  4. 4.Take 75 and take away the sum of its digits. What do you get?
  5. 5.42?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.8?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 46 and take away the sum of its digits. What do you get?
  8. 8.Take 21 and take away the sum of its digits. What do you get?
  9. 9.7?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 57 and take away the sum of its digits. What do you get?
  11. 11.14?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.55?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?557 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.55?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 83 and take away the sum of its digits. What do you get?
  17. 17.Take 60 and take away the sum of its digits. What do you get?
  18. 18.Take 28 and take away the sum of its digits. What do you get?
  19. 19.?402 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 31 and take away the sum of its digits. What do you get?
  21. 21.28?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 17 and take away the sum of its digits. What do you get?
  23. 23.3?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 71 and take away the sum of its digits. What do you get?
  25. 25.649? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 34 and take away the sum of its digits. What do you get?
  28. 28.?314 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?758 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.8?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 27 and take away the sum of its digits. What do you get?
  32. 32.25?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 30 and take away the sum of its digits. What do you get?
  34. 34.?336 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.294? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 16 and take away the sum of its digits. What do you get?
  37. 37.Take 73 and take away the sum of its digits. What do you get?
  38. 38.Take 19 and take away the sum of its digits. What do you get?
  39. 39.9?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 33 and take away the sum of its digits. What do you get?

Answer key

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

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