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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 248 · 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. 1.8?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.64?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?794 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 36 and take away the sum of its digits. What do you get?
  6. 6.Take 49 and take away the sum of its digits. What do you get?
  7. 7.?840 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.781? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 64 and take away the sum of its digits. What do you get?
  10. 10.453? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 82 and take away the sum of its digits. What do you get?
  12. 12.434? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 52 and take away the sum of its digits. What do you get?
  15. 15.?096 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 35 and take away the sum of its digits. What do you get?
  17. 17.Take 56 and take away the sum of its digits. What do you get?
  18. 18.?242 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.504? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.6?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 23 and take away the sum of its digits. What do you get?
  22. 22.?446 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?143 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.457? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 68 and take away the sum of its digits. What do you get?
  27. 27.47?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?394 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 12 and take away the sum of its digits. What do you get?
  30. 30.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.64? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 21 and take away the sum of its digits. What do you get?
  33. 33.578? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 41 and take away the sum of its digits. What do you get?
  35. 35.?705 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 99 and take away the sum of its digits. What do you get?
  37. 37.Take 37 and take away the sum of its digits. What do you get?
  38. 38.?083 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.701? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?969 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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