# Homework 26, problem 3 -- solution.

class Calculator:
    def __init__(self):
        self.value = 0

    def add(self, n):
        self.value += n

    def sub(self, n):
        self.value -= n

    def mul(self, n):
        self.value *= n

    def show(self):
        print(f"Value: {self.value}")

calc = Calculator()
calc.add(10)
calc.show()
calc.mul(3)
calc.show()
calc.sub(5)
calc.show()