To simplify the expression 5^4 × 20^4 / 25^5 × 4^5, we can break it down step by step:

First, let's simplify the exponents:
5^4 = 5 × 5 × 5 × 5 = 625
20^4 = 20 × 20 × 20 × 20 = 160,000
25^5 = 25 × 25 × 25 × 25 × 25 = 9,765,625
4^5 = 4 × 4 × 4 × 4 × 4 = 1,024

Now, substitute these values back into the expression:
625 × 160,000 / 9,765,625 × 1,024

Next, let's simplify the numerator and denominator separately:
625 × 160,000 = 100,000,000
9,765,625 × 1,024 = 10,000,000,000

Now, substitute these simplified values back into the expression:
100,000,000 / 10,000,000,000

Finally, divide the numerator by the denominator:
100,000,000 / 10,000,000,000 = 0.01

Therefore, 5^4 × 20^4 / 25^5 × 4^5 simplifies to 0.01.