#!/usr/bin/python PRICE=123.45 PAID=1300.0 change=PAID-PRICE # Find largest denomination c=-3 while True: if int(change/pow(10,c)) == 0: break c += 1 while change>0: c-=1 denomination = pow(10,c) bills = int(change/denomination) print "%d-%fs" % (bills,denomination) change -= bills*denomination change = round(change,2)