If it's a dog (>=2.00) just subtract 1 and multiply by 100.
so 3.40 = +240
(<b>3.40</b> - 1) * 100 = +240
If it's a favorite (<=2.00), multiply by 100, subtract 100, and then divide -10000 by what you have.
So 1.67 = -149
-10000 / [(<b>1.67</b> * 100) - 100] = -149