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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 817 · 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. 1.272? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.46?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?236 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.802? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.10?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 83 and take away the sum of its digits. What do you get?
  7. 7.Take 48 and take away the sum of its digits. What do you get?
  8. 8.465? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?763 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.11?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 78 and take away the sum of its digits. What do you get?
  13. 13.Take 24 and take away the sum of its digits. What do you get?
  14. 14.Take 68 and take away the sum of its digits. What do you get?
  15. 15.?887 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?869 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.625? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 93 and take away the sum of its digits. What do you get?
  19. 19.633? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.72?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 11 and take away the sum of its digits. What do you get?
  22. 22.2?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.88?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 35 and take away the sum of its digits. What do you get?
  26. 26.Take 75 and take away the sum of its digits. What do you get?
  27. 27.8?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 91 and take away the sum of its digits. What do you get?
  29. 29.Take 31 and take away the sum of its digits. What do you get?
  30. 30.?334 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.54?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.70?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?338 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?251 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.378? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?705 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 44 and take away the sum of its digits. What do you get?
  40. 40.?725 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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