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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 353 · 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.?983 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?188 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 68 and take away the sum of its digits. What do you get?
  5. 5.?283 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 43 and take away the sum of its digits. What do you get?
  7. 7.856? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.9?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 89 and take away the sum of its digits. What do you get?
  10. 10.712? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?935 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.6?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 31 and take away the sum of its digits. What do you get?
  14. 14.Take 51 and take away the sum of its digits. What do you get?
  15. 15.Take 73 and take away the sum of its digits. What do you get?
  16. 16.?546 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 71 and take away the sum of its digits. What do you get?
  18. 18.4?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 56 and take away the sum of its digits. What do you get?
  20. 20.899? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 18 and take away the sum of its digits. What do you get?
  22. 22.3?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?348 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.551? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 23 and take away the sum of its digits. What do you get?
  27. 27.8?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.217? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 12 and take away the sum of its digits. What do you get?
  30. 30.Take 52 and take away the sum of its digits. What do you get?
  31. 31.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 54 and take away the sum of its digits. What do you get?
  33. 33.Take 87 and take away the sum of its digits. What do you get?
  34. 34.Take 72 and take away the sum of its digits. What do you get?
  35. 35.3?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?377 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.265? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 45 and take away the sum of its digits. What do you get?

Answer key

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

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