Количество следы за племени в факторе числа.
# Number of trailing zeros in a factorial of a number
def zeros(n)
zeros = 0
while (n > 0)
n = (n / 5).floor
zeros += n
end
zeros
end
print "Number of trailing zeros = ", zeros(6); # 1
print "\nNumber of trailing zeros = ", zeros(30); # 7
Mackerel