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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 144 · 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. 1.7?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.69?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 36 and take away the sum of its digits. What do you get?
  4. 4.6?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.95? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 18 and take away the sum of its digits. What do you get?
  7. 7.Take 44 and take away the sum of its digits. What do you get?
  8. 8.?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.648? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.5?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 73 and take away the sum of its digits. What do you get?
  13. 13.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?910 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.7?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 50 and take away the sum of its digits. What do you get?
  17. 17.643? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 65 and take away the sum of its digits. What do you get?
  19. 19.47? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 39 and take away the sum of its digits. What do you get?
  21. 21.543? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 35 and take away the sum of its digits. What do you get?
  23. 23.7?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?574 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 70 and take away the sum of its digits. What do you get?
  27. 27.43?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 16 and take away the sum of its digits. What do you get?
  30. 30.Take 77 and take away the sum of its digits. What do you get?
  31. 31.?932 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.73? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 28 and take away the sum of its digits. What do you get?
  34. 34.5?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.333? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.69?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.166? 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. 6
  3. 27
  4. 1
  5. 4
  6. 9
  7. 36
  8. 1
  9. 9
  10. 5
  11. 8
  12. 63
  13. 5
  14. 8
  15. 6
  16. 45
  17. 5
  18. 54
  19. 7
  20. 27
  21. 6
  22. 27
  23. 2
  24. 2
  25. 3
  26. 63
  27. 5
  28. 9
  29. 9
  30. 63
  31. 4
  32. 8
  33. 18
  34. 2
  35. 2
  36. 8
  37. 9
  38. 4
  39. 9
  40. 5

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