Well, you have the variables switched around.. It would be this

int average = scoreSum/count

In order to get the Sum of the Scores, you have to add them to a variable each time you get a score in.

__So basically, here's the logic:__
*I have a count variable of length (let's make something up) 5.*

Therefore, I must have 5 scores.

If I want to get the average, I must find the sum of the scores.

The score variable changes every time I run my loop, so simply multiplying the score by 5 at the end won't work.

So in all, I must find a way that I can add each individual score to "something" 5 times... You can go from here, it's best to learn from Trial & Error
And if you want to display the maximum grade, you have to have a variable that changes every time a higher number comes..

This concept is a little harder, but first, try to get the Average section working.