math help please...

[DangerPaul]

I am going completely retarded today or something. I need to figure out the % increase in something. For instance, if my original reading was 40 CFM and is now 44 CFM I know that is 10% by looking at it, but how do I come up with it mathmatically?

Examples...

Original reading was 484 CFM, and it is now 615 CFM, what is the math formula to figure out its increase in a percentage? Help please.

[Eziekial]

((X-Y)/X) * 100=% change figure out the +/- based on the #s

[DangerPaul]

Sigh... thank you sir.