Out of Outa's

It is used when you reach the maximum score of a test or graded assignment many times.

Let's just say you check your graded assignments and see you received many of 10 out of 10's, 12 out of 12's, etc. Instead of being specific and naming how many out of 10's or 12's you've received, you would say, for example, "Damn! I got a lot of out of outa's!"