Welcome 2016! Part 21

Algebra Level 4

$\large \dfrac{5}{1 \times 3}+\dfrac{5}{2\times 4}+\dfrac{5}{3 \times 5}+\dfrac{5}{4\times 6}+\cdots = \dfrac{A}{B}$

Given that $A$ and $B$ are coprime positive integers, find $A-B$ .