Merged all files. It is a trick. If you want to know RTFM.
# round using intn = 17.3 # any floatint (n + .5)# round it off to first decimal placeround(amount * 10) / 10.0# round it off to nearest 5 paiseround(amount * 20) / 20.0# exchange two variablesa, b = b, a