Expose keyboard shortcuts seem to already be taken; i'm confused; help?

Question

Hello,
I'm a mac newbie. Under the mac help instructions for expose, I find these instructions:
xposé provides a quick way to see all open application windows and switch between them. Press the F9 key to see all the windows you have open, or press the F10 key to see the open windows in the application you are currently using. To hide all open windows so you can see the desktop, press F11.
What I find is that f9, f10, and f11 are taken with other shortcuts on the keyboard and I can never get the expose shortcuts to work. I've played around and find no way around this.
What am I doing wrong?
Thanks.

Answer 1

Ray, Thanks for the very helpful response.
To add to your discovery, it also appears that under system preferences/keyboard, there is a box that is defaulted "unchecked" that reads, "Use all F1, F2, etc. keys as standard function keys. When this option is selected, press the FN key to use the special features printed on each key."
That is why my keyboard is over-riding the function keys b/c it is unchecked. When I check this box the expose works as intended.
I also find that my mouse is set up to have the "side" buttons linked with expose.
Under the keyboard shortcuts, I can see where I can check/uncheck the keyboard options but not change them. Still playing around with it...but you definitely solved it for me.
I will mark as such. Good work! Thanks.