I was looking for a military stack exchange but i don't see one.

My guess is that you try to commit roughly equal troops to multiple engagements and hope that while you might lose more at each engagement eventually all enemies will be causalities.

EDIT: Equally equipped, equally skilled.

What I was thinking is simply trying to overwhelm your enemy with your numbers all at once would fail: friendly fire and friendlies in general getting in each other's way. In an unarmed fight, any more than 3 to 1 has similar problems (this i read in a book about prison).