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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 341 · 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. 1.5?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.582? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 96 and take away the sum of its digits. What do you get?
  4. 4.Take 81 and take away the sum of its digits. What do you get?
  5. 5.?449 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 38 and take away the sum of its digits. What do you get?
  7. 7.6?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.457? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.89?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.62?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 34 and take away the sum of its digits. What do you get?
  13. 13.Take 92 and take away the sum of its digits. What do you get?
  14. 14.Take 86 and take away the sum of its digits. What do you get?
  15. 15.Take 74 and take away the sum of its digits. What do you get?
  16. 16.?569 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.4?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.38?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.5?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 55 and take away the sum of its digits. What do you get?
  21. 21.Take 50 and take away the sum of its digits. What do you get?
  22. 22.10?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 83 and take away the sum of its digits. What do you get?
  25. 25.68?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.152? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 31 and take away the sum of its digits. What do you get?
  29. 29.Take 62 and take away the sum of its digits. What do you get?
  30. 30.Take 39 and take away the sum of its digits. What do you get?
  31. 31.347? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.65?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 53 and take away the sum of its digits. What do you get?
  34. 34.2?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.61?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.27?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.782? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 48 and take away the sum of its digits. What do you get?
  39. 39.Take 59 and take away the sum of its digits. What do you get?
  40. 40.8?67 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. 3
  3. 81
  4. 72
  5. 1
  6. 27
  7. 9
  8. 2
  9. 8
  10. 4
  11. 3
  12. 27
  13. 81
  14. 72
  15. 63
  16. 7
  17. 9
  18. 7
  19. 8
  20. 45
  21. 45
  22. 3
  23. 1
  24. 72
  25. 6
  26. 1
  27. 4
  28. 27
  29. 54
  30. 27
  31. 4
  32. 1
  33. 45
  34. 4
  35. 4
  36. 9
  37. 1
  38. 36
  39. 45
  40. 6

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