`( 5^4 . 2^4)/( 5^2 . 20^5)`
`= ( 5^4 . 2^4)/( 5^2 . (2^2 . 5)^5)`
`= ( 5^4 . 2^4)/( 5^2 . 2^10 . 5^5)`
`= ( 5^4 . 2^4)/( ( 5^2 . 5^5) . 2^10)`
`= ( 5^4 . 2^4)/( 5^7 . 2^10)`
`= ( 5^4 . 2^4)/( 5^4 . 5^3 . 2^4 . 2^6)`
`= ( 1 . 1)/( 1 . 5^3 . 1 . 2^6)`
`= (1)/( 125 . 64)`
`=1/8000`
`#caty09`