プログラミング　計算順序について

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Created by devel on 2017/07/27.

import math



def main():
    a = (2 + 2) / (2 * 10)
    b = (2 + 2) / 2 * 10
    
    print(a) 
    # 0.2
    print(b)
    # 20.0 

if __name__ == '__main__':
    main()