Bracket , Division, Multiplication, Addition and substraction
let width: Double = 7
width/2 // 3.5
width % height
let wid:Double = 10
let hei:Double = 6
width.truncatingRemainder(dividingBy: height)
var x=5
x=x+1
x +=1
!(width < height)
var a = 10
var b: Double = Double(a)