Mystery Numbers

 

  1. I think of a mystery number. I take away 13. I get 30. What was my mystery number?
  2. I think of a mystery number. I halve it and then take away 2. I get 8. What was my mystery number?
  3. I think of a mystery number. I double it and then add 9. I get 57. What was my mystery number?

Can you write three mystery number clues of your own?