Question about Exposure adjustment

[Xen]

When you open your RAW file in LR you have the option to change the exposure.  Can anyone tell me what the exposure changes equal to?  For instance....if I press the arrow two times to the right, does that give me a photo that is equivalent to +2 if it was read in exif data?

There are also two ways to change exposure.  The 'one arrow' and then the 'two arrow'.  What do they equal?  

Thanks!!

[61Dynamic]

The single arrow is 1/3rd stop and the double is 1 stop.

[Xen]

thanks!!