from functools import reduce


def str2num(s):
    return float(s) #改为转化小数


def calc(exp):
    ss = exp.split('+')
    ns = map(str2num, ss)
    return reduce(lambda acc, x: acc + x, ns)


def main():
    # 添加错误捕获并返回错误类型
    try:
        r = calc('100 + 200 + 345')
        print('100 + 200 + 345 =', r)
        r = calc('99 + 88 + 7.6')
        print('99 + 88 + 7.6 =', r)
    expect Exection as e:
        print(e)


main()