Hi there :-)!
I will show you how to use the In-Game Calculator that not many players in world of warcraft knows about!
I actually knew this for years and years, but today i tried it off again to see if it still were there and it was!
I remember how i used to do my home work in WoW while i were playing (lol)
Anyways, by typing the following command in chat "/run print (x+x)" without the brackets of course, you have yourself a easily accessible in-game calculator. To anyone who has checked the API this would seem retardedly obvious, but a lot of people dont know about this like i mentioned before :-)!
This is how it should be written for an example:
/run print (9x7x9)
Picture:
Also remember that you can use ( /, *,-,+ )
Have fun!