Hi
I’m working my way through the power point I have been given by my college however I’m struggling to figure out how they work out the bottom two lines if that makes sense?
Cheers

 

It looks to me like your system doesn't have the font used in the original file and you're seeing gibberish characters where there should be mathematical operators. You can, if you want, post a slide or two of the file here and others can see how they look.