Proportionality equation

I try not to get riled up in my blog about Israel attacking Gaza because it is not a subject on which I have any credibility at all.  I call myself an Israeli-American, an heir to the group once called Jews.

I do want to raise a moral question, since moral questions are one of my fortes.  Most of the anti-Semites in the world, which are 96% of the leaders of UN member nations, politely demand that the Israeli military defense be 'proportional'. What is proportional?

In my moral crayon box the proportionality equation is something like this: 

1a = 867b

killing one peace-loving-innocent citizen of a peace-loving nation =

killing in retribution 867 enemy soldiers who hide among civilians; the 867 includes any number of close-in civilians who teach their children to live a life of murder in a country dedicated to genocide.

What does your moral equation look like?