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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 586 · 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. 1.4?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 42 and take away the sum of its digits. What do you get?
  3. 3.?708 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 12 and take away the sum of its digits. What do you get?
  6. 6.1?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 49 and take away the sum of its digits. What do you get?
  8. 8.?488 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.1?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.13?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 65 and take away the sum of its digits. What do you get?
  12. 12.177? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.1?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.7?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 90 and take away the sum of its digits. What do you get?
  16. 16.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?917 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 71 and take away the sum of its digits. What do you get?
  19. 19.?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.38?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 55 and take away the sum of its digits. What do you get?
  23. 23.?287 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?656 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 53 and take away the sum of its digits. What do you get?
  26. 26.?860 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 52 and take away the sum of its digits. What do you get?
  28. 28.Take 14 and take away the sum of its digits. What do you get?
  29. 29.1?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 47 and take away the sum of its digits. What do you get?
  31. 31.34?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.69?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.870? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.2?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.4?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.7?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?507 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 91 and take away the sum of its digits. What do you get?

Answer key

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

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