Splitting the Screen on a Mac

I have put several posts up about the importance of being able to split a screen especially in my county where all 6 - 12th grade students have e-books in social studies.  Here is how I do it in Explorer and Firefox (you can't do it in Chrome without their insert) and here is how you can do it easily by dragging it to a corner on a Mac (as opposed to taking the time to resize it.  I will tell you that it does cost $7 and I get nothing from Cinch (who makes it) by telling you about it.