def add(x, y):
    return x+y


def subtract(x, y):
    return x-y


def divide(x, y):
    if y==0:
        print('cannot divide by 0')
        return
    return x/y


def multiply(x, y):
    return x*y


def square(x):
    return x**2


def power(x, y):
    return x**y


def sqrt(x):
    return power(x,1/2)

