Here's what you can do:
1) Have the hero talk to an NPC.
2) In the event commands, page 1, select "Change Variable"
3) Name variable#0001 "experience points"
4) Set variable "experience points" to -Hero(pick which hero): Exp. (Hero is the sixth option down)
5) Click OK
6) In the event commands, page 2, select "Show Message"
---THIS IS THE IMPORTANT PART---
7) Type something like, "Hero, you have earned \V[1] experience points!"
The answer to your question is the \V[1]. That will display the value in variable# 0001, which we named experience points.
It must look like this! \V[1]. If you want to show the value in variable# 0007, you'd type \V[7]. Got it?