from random import randint
results = []
for i in range(1000000):
numbers = range(100) # list with 100 elements [0, 1, ... 99]
look_for_this_number = randint(0, len(numbers)-1)
result = 0
for j in range(5): # pick 5 random numbers from the list
ri = randint(0, len(numbers)-1)
number = numbers.pop(ri)
if look_for_this_number == number: result = 1 # correct number picked!
results.append(result)
print "p:", sum(results)/float(len(results))