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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 285 · 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. 1.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?851 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.63?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?53 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. 7.75?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 18 and take away the sum of its digits. What do you get?
  9. 9.Take 27 and take away the sum of its digits. What do you get?
  10. 10.65?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 43 and take away the sum of its digits. What do you get?
  12. 12.6?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?895 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 85 and take away the sum of its digits. What do you get?
  15. 15.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 17 and take away the sum of its digits. What do you get?
  17. 17.513? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.205? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 30 and take away the sum of its digits. What do you get?
  20. 20.9?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.6?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 65 and take away the sum of its digits. What do you get?
  23. 23.6?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 56 and take away the sum of its digits. What do you get?
  25. 25.?358 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?469 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.74? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.3?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.159? 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. 35.42?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?296 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?129 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 42 and take away the sum of its digits. What do you get?
  39. 39.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 34 and take away the sum of its digits. What do you get?

Answer key

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

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