If I bomb a territory with a commander and 20 armies on it does it:
a) Result in a commander and 10 armies remaining?
b) Result in a commander and 7 armies remaining since commander is effectively 7 and half 27 is 14 (thus commander(7) + 7 armies)?

I am guessing a), but would love to know if anyone knows for certain.

Pretty simply commanders are worth +7
They are not multiplied.
if you place 20 armies on your commander it has a strength of 27
if a commander is alone with no armies it is worth 7.

I realize that Tim... but how does a bomb work on a commander? That was my question

Yes, it is a).

https://www.warlight.net/MultiPlayer?GameID=10951694
Bomb cards used on turns 5 and 6.

Yeah, for "troop count" the commander seems to be valued at zero. Same for other interations with the game, such as army cap :)

It's only "worth" 7 in attack and defence.

perfect rakleader! Answers my question precisely. Thanks.

Interesting that 7 went to 3 though with a commander on it as normally 7 goes to 4. I guess commander counts as 1 unit with respect to bombing.

Edited 5/11/2016 21:33:31

7 always go to 3, killed unites are rounded up = remaining are rounded now, no matter if there is commander or no

Thank Krzychu... I am wrong too many times today :)

The commander is valued at 0 in regard to cards/settings.