<I have got error in my simple kotlin calculator> ...

# stackoverflow

[user]

I have got error in my simple kotlin calculator
When I run this code, I have a problem. I want to build a simple calculator, so I need to use readLine() but I face error in subtraction, multiplication and division operations. This is the code, Please help me.
fun main()
{
print("1. Addition\n2. Subtraction\n3. Multiplication\n4. Division\nChoose Number: ")

var choosen = readLine()

print("Enter The First Number: ")

var num1 = readLine()

print("Enter The Second Number: ")

var num2 = readLine()

if (choosen?.toInt() == 1){...