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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 905 · 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. 1.64?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.50?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.49?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 56 and take away the sum of its digits. What do you get?
  6. 6.?614 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 65 and take away the sum of its digits. What do you get?
  8. 8.?120 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 48 and take away the sum of its digits. What do you get?
  10. 10.11?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.91? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.427? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 22 and take away the sum of its digits. What do you get?
  14. 14.854? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.4?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 29 and take away the sum of its digits. What do you get?
  17. 17.Take 14 and take away the sum of its digits. What do you get?
  18. 18.362? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.69?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?676 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.548? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.2?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.54?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?056 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.20? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.782? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.103? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.8?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.750? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 93 and take away the sum of its digits. What do you get?
  32. 32.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 87 and take away the sum of its digits. What do you get?
  34. 34.4?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 76 and take away the sum of its digits. What do you get?
  36. 36.?839 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 44 and take away the sum of its digits. What do you get?
  38. 38.Take 25 and take away the sum of its digits. What do you get?
  39. 39.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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