I have a question for homework regarding unix.?

Here is the question: Give a command line to display the types of all the files in your ~/unix directory that start with the word chapter, are followed by a digit 1,2,6,8,9 and end with .eps or .prn the solution that i came up with is this: ls chapter[12689]*.eps; ls chapter[12689]*.prn now my question to you is how can i combine that without having to use the semicolen, i know there is a command but i can't think of it. Please help!