pub fn add(first: usize, second: usize) -> usize {
first + second
}
pub fn remove(first: usize, second: usize) -> usize {
first - second
}
pub fn multiply(first: usize, second: usize) -> usize {
first * second
}
pub fn divide(first: usize, second: usize) -> usize {
first / second
}