// A=4

// B=3

// C=2

// D=1

// F=0

​

var mathClass = 4

var englishClass = 3

var scienceClass = 3

var peClass = 4

var historyClass = 3

var computerScienceClass = 3

var danceClass = 4

​

var average =(mathClass + 

              englishClass + 

              scienceClass + 

              peClass + 

              historyClass + 

              computerScienceClass + 

              danceClass)/7

​

console.log(average)