from functools import reduce

def str2num(s):

return float(s)

def calc(exp):

ss = exp.split('+')

ns = map(str2num, ss)

return reduce(lambda acc, x: acc + x, ns)

def main():

r = calc('100 + 200 + 345')

print('100 + 200 + 345 =', r)

r = calc('99 + 88 + 7.6')

print('99 + 88 + 7.6 =', r)

main()