Answer 1

What is it supposed to do?

What does
println(7%)
mean?

If you want to print the string, you need the double quotes:
println("7%")

Answer 2

In first print statement one operand is missing give more description about your code while posting questions

fun main(args: Array<String>) {
var total = 200
println(7%total)
var a =7
println(total/a)
}