Beginners projects

Hello, my name is Steve.

I have managed to get myself a university placement year working on a mainframe using COBOL.
I begin my job in September and have purchased a book I was recommended by a former COBOL dev.

I want to learn the language by coding and I would like to write programs that are not from the book (Murachs Mainframe COBOL). However, I am not sure what ideas I could program as a beginner to the language. I see most systems are for transactions and number crunching, however, I am stuck on a few ideas.

Any help is greatly appreciated as I am enjoying writing the language and understanding the different concepts to modern languages. Also, apologies if this is not the correct place to post this. It seemed like the correct place.

Best regards,