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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 688 · 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. 1.1?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?031 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 52 and take away the sum of its digits. What do you get?
  5. 5.Take 77 and take away the sum of its digits. What do you get?
  6. 6.4?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?471 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.26?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 78 and take away the sum of its digits. What do you get?
  14. 14.Take 88 and take away the sum of its digits. What do you get?
  15. 15.Take 73 and take away the sum of its digits. What do you get?
  16. 16.Take 16 and take away the sum of its digits. What do you get?
  17. 17.Take 92 and take away the sum of its digits. What do you get?
  18. 18.190? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?408 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?325 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?274 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.589? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 85 and take away the sum of its digits. What do you get?
  26. 26.6?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 37 and take away the sum of its digits. What do you get?
  28. 28.556? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.213? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.17?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 48 and take away the sum of its digits. What do you get?
  32. 32.433? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 82 and take away the sum of its digits. What do you get?
  34. 34.Take 74 and take away the sum of its digits. What do you get?
  35. 35.Take 33 and take away the sum of its digits. What do you get?
  36. 36.37?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?175 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?363 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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