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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 282 · 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. 1.3?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 82 and take away the sum of its digits. What do you get?
  4. 4.Take 48 and take away the sum of its digits. What do you get?
  5. 5.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 20 and take away the sum of its digits. What do you get?
  7. 7.?718 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 47 and take away the sum of its digits. What do you get?
  9. 9.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.671? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 94 and take away the sum of its digits. What do you get?
  12. 12.802? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 35 and take away the sum of its digits. What do you get?
  15. 15.2?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 60 and take away the sum of its digits. What do you get?
  17. 17.8?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 70 and take away the sum of its digits. What do you get?
  19. 19.Take 12 and take away the sum of its digits. What do you get?
  20. 20.Take 99 and take away the sum of its digits. What do you get?
  21. 21.?190 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.35? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 65 and take away the sum of its digits. What do you get?
  24. 24.?471 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.1?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.113? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.56?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.146? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 23 and take away the sum of its digits. What do you get?
  31. 31.Take 91 and take away the sum of its digits. What do you get?
  32. 32.45?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 76 and take away the sum of its digits. What do you get?
  34. 34.4?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.7?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?470 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.2?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.747? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?959 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?615 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. 1
  3. 72
  4. 36
  5. 3
  6. 18
  7. 2
  8. 36
  9. 6
  10. 4
  11. 81
  12. 8
  13. 1
  14. 27
  15. 4
  16. 54
  17. 4
  18. 63
  19. 9
  20. 81
  21. 8
  22. 1
  23. 54
  24. 6
  25. 5
  26. 5
  27. 4
  28. 1
  29. 7
  30. 18
  31. 81
  32. 2
  33. 63
  34. 7
  35. 2
  36. 7
  37. 4
  38. 9
  39. 4
  40. 6

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