pot odds I can do in my head within seconds and know where I am at, and outs are easy to count. Those are both fast and easy, and reads are not that hard to do either, especially if you take good notes. I was always good at math though, so it don't take anytime for me to know that calling 150 in a 700 pot is slightly under 5:1, and I know basically which hands are good to call with in that range. I was always good at math, and the more you play, the more similar situations you will run into, and can make decisions based on similar situations and the texture of the table based on that.