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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 332 · 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.?613 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 78 and take away the sum of its digits. What do you get?
  3. 3.Take 24 and take away the sum of its digits. What do you get?
  4. 4.Take 99 and take away the sum of its digits. What do you get?
  5. 5.?236 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 16 and take away the sum of its digits. What do you get?
  7. 7.?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.62?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.24?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.105? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 63 and take away the sum of its digits. What do you get?
  13. 13.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.1?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 22 and take away the sum of its digits. What do you get?
  17. 17.43?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.74? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 52 and take away the sum of its digits. What do you get?
  20. 20.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?817 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 15 and take away the sum of its digits. What do you get?
  23. 23.8?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 54 and take away the sum of its digits. What do you get?
  25. 25.Take 65 and take away the sum of its digits. What do you get?
  26. 26.Take 57 and take away the sum of its digits. What do you get?
  27. 27.6?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.294? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.5?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.2?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?815 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.2?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.42?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 23 and take away the sum of its digits. What do you get?
  35. 35.Take 66 and take away the sum of its digits. What do you get?
  36. 36.Take 80 and take away the sum of its digits. What do you get?
  37. 37.Take 67 and take away the sum of its digits. What do you get?
  38. 38.6?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?020 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.7?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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