I have been reading a fair bit of military history lately and I have questions that are so basic I'm kind of embarrassed to asked them. 1. What is a division? I understand that it's a group of smaller groups, but don't understand why the division seems cross national lines. For example, in the Battle of the Bulge, we had X number of divisions to Germany's Y number of divisions. Are divisions always the same size, even in other countries' armies? 2. Multiple armies. Example: The 3rd Army, the 6th Army. Isn't it all just the Army? 3. NCOs vs. commissioned officers. Is it just a matter of rank? Do you have to be commissioned to be promoted past sergeant, or can you obtain a higher rank and still be an NCO? Thanks.