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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 661 · 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.Take 88 and take away the sum of its digits. What do you get?
  2. 2.873? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.36?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.6?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?885 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.29?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.31?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?110 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 52 and take away the sum of its digits. What do you get?
  11. 11.Take 83 and take away the sum of its digits. What do you get?
  12. 12.Take 21 and take away the sum of its digits. What do you get?
  13. 13.6?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?511 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?312 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.243? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?248 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.77?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 65 and take away the sum of its digits. What do you get?
  20. 20.?012 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?481 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?451 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 60 and take away the sum of its digits. What do you get?
  24. 24.3?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 40 and take away the sum of its digits. What do you get?
  26. 26.Take 24 and take away the sum of its digits. What do you get?
  27. 27.?539 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?169 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.509? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.4?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.19?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?295 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?475 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?520 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 28 and take away the sum of its digits. What do you get?
  39. 39.?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 94 and take away the sum of its digits. What do you get?

Answer key

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

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