C# functional parsing combinators library

(a + (b * 5) / 2) - (a * b * 5) / 7
Perform simplification
(a + b * 5/2) - a * b * 5/7
Perform substitution
a = 25
b = 11
(25 + 11 * 5/2) - 25 * 11 * 5/7
Perform simplification
-2015/14