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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 683 · 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 48 and take away the sum of its digits. What do you get?
  2. 2.22? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 51 and take away the sum of its digits. What do you get?
  4. 4.Take 30 and take away the sum of its digits. What do you get?
  5. 5.Take 96 and take away the sum of its digits. What do you get?
  6. 6.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.77?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 94 and take away the sum of its digits. What do you get?
  9. 9.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.8?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?983 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.379? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.683? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.3?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 71 and take away the sum of its digits. What do you get?
  17. 17.Take 90 and take away the sum of its digits. What do you get?
  18. 18.Take 22 and take away the sum of its digits. What do you get?
  19. 19.34?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.5?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 59 and take away the sum of its digits. What do you get?
  24. 24.Take 67 and take away the sum of its digits. What do you get?
  25. 25.Take 24 and take away the sum of its digits. What do you get?
  26. 26.502? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.505? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.5?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.367? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.815? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?320 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.366? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.6?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 32 and take away the sum of its digits. What do you get?
  36. 36.Take 66 and take away the sum of its digits. What do you get?
  37. 37.Take 33 and take away the sum of its digits. What do you get?
  38. 38.2?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 86 and take away the sum of its digits. What do you get?
  40. 40.303? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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