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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 894 · 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 83 and take away the sum of its digits. What do you get?
  2. 2.Take 51 and take away the sum of its digits. What do you get?
  3. 3.Take 85 and take away the sum of its digits. What do you get?
  4. 4.4?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.225? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 12 and take away the sum of its digits. What do you get?
  8. 8.54?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.36?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 78 and take away the sum of its digits. What do you get?
  11. 11.56?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 18 and take away the sum of its digits. What do you get?
  14. 14.48? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 25 and take away the sum of its digits. What do you get?
  16. 16.8?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.227? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.5?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 57 and take away the sum of its digits. What do you get?
  20. 20.?588 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.3?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 87 and take away the sum of its digits. What do you get?
  23. 23.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.7?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.7?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.3?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.202? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.90? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?466 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?563 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?629 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 66 and take away the sum of its digits. What do you get?
  33. 33.Take 20 and take away the sum of its digits. What do you get?
  34. 34.6?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?791 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.3?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?354 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?437 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 80 and take away the sum of its digits. What do you get?

Answer key

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

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