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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 408 · 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. 1.456? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 34 and take away the sum of its digits. What do you get?
  3. 3.?052 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 69 and take away the sum of its digits. What do you get?
  5. 5.Take 44 and take away the sum of its digits. What do you get?
  6. 6.Take 40 and take away the sum of its digits. What do you get?
  7. 7.Take 76 and take away the sum of its digits. What do you get?
  8. 8.2?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?687 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?715 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 30 and take away the sum of its digits. What do you get?
  13. 13.Take 19 and take away the sum of its digits. What do you get?
  14. 14.Take 14 and take away the sum of its digits. What do you get?
  15. 15.7?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?172 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.1?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.63?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?483 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?224 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?155 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.7?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 16 and take away the sum of its digits. What do you get?
  25. 25.?078 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 98 and take away the sum of its digits. What do you get?
  27. 27.Take 75 and take away the sum of its digits. What do you get?
  28. 28.1?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 41 and take away the sum of its digits. What do you get?
  30. 30.Take 96 and take away the sum of its digits. What do you get?
  31. 31.Take 90 and take away the sum of its digits. What do you get?
  32. 32.?263 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 73 and take away the sum of its digits. What do you get?
  34. 34.490? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?695 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.514? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?996 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?304 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.548? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.180? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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