Leveling up is pretty basic, the value shown on the right in the EXP stat is how much exp you need to level up, gaining that much exp nets you a level up. It does not show cumulative exp. The EXP stat only shows the requirement and progress for the next level.

So you need 10 exp to reach level 2, right? If you gain 11 exp right now, you'll reach level 2, and your exp stat will say "1/x" where X is the amount needed to get level 3, because 10 of the 11 exp you just got brought you to level 2, and so the 11th exp point is put towards reaching level 3 instead of being wasted.

Mercury is at work today so I'm waiting for him to come home to collaborate on Combat. He gave me free-reign of Crafting so I finished that.