n! means n x (n - 1) x ... x 3 x 2 x 1

Find the sum of the digits in the number 100!

1
2

reduce (lambda x,y: int (x) + int (y),
str (reduce (lambda x,y: x * y, xrange (100, 0, -1))))

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

Find the sum of all the even-valued terms in the sequence which do not exceed four million.

1
2
3
4
5
6
7

def fibonacci(limit):
    a, b = 0, 1
    while a < limit:
    yield a
    a, b = b, a + b

print sum (filter (lambda x: x % 2 == 0, fibonacci (4e6)))