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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 81 · 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.?763 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?712 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 62 and take away the sum of its digits. What do you get?
  4. 4.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.1?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?040 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 13 and take away the sum of its digits. What do you get?
  8. 8.281? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 42 and take away the sum of its digits. What do you get?
  10. 10.546? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?658 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 61 and take away the sum of its digits. What do you get?
  15. 15.Take 35 and take away the sum of its digits. What do you get?
  16. 16.?967 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.99? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?386 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 36 and take away the sum of its digits. What do you get?
  20. 20.?070 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.6?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 85 and take away the sum of its digits. What do you get?
  24. 24.?389 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 58 and take away the sum of its digits. What do you get?
  26. 26.35?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.32? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 84 and take away the sum of its digits. What do you get?
  31. 31.?404 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 75 and take away the sum of its digits. What do you get?
  33. 33.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?037 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?804 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 91 and take away the sum of its digits. What do you get?
  38. 38.51?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 38 and take away the sum of its digits. What do you get?
  40. 40.?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 2
  2. 8
  3. 54
  4. 1
  5. 3
  6. 5
  7. 9
  8. 7
  9. 36
  10. 3
  11. 7
  12. 8
  13. 3
  14. 54
  15. 27
  16. 5
  17. 9
  18. 1
  19. 27
  20. 2
  21. 3
  22. 2
  23. 72
  24. 7
  25. 45
  26. 5
  27. 3
  28. 2
  29. 4
  30. 72
  31. 1
  32. 63
  33. 4
  34. 3
  35. 8
  36. 6
  37. 81
  38. 9
  39. 27
  40. 5

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