Can I make an afghan out of different shaped squares?

I have a stitch book (for Knit ) that I wanted to try making different squares with and then sewing or crocheting them together to make an afghan. Only problem is that they are all different ... formulas i guess?? Like one will say mulitple of 4 plus two. While another will say odd number of stitches and then another will say 8 plus 4. That sort of thing. am I going to be stuck with a bunch or mismatched squares that I won't be able to crochet together for the afghan I want??