2+2=?

I read this article about a family who spent five years in Russia as expatriates and sent their children to a Russian school. The article in itself is interesting, but even more interesting is this quote from the school's director, Vasiliy Bogin:

“Does 2 + 2 = 4? No! Because two cats plus two sausages is what? Two cats. Two drops of water plus two drops of water? One drop of water.”

Well...I guess it depends on whether we are taking two plus two or whether we are taking two "something" plus two "something"...

The quote can be found on page 4 of the article:

When I asked Bogin to explain Shchedrovitsky, he asked a question. “Does 2 + 2 = 4? No! Because two cats plus two sausages is what? Two cats. Two drops of water plus two drops of water? One drop of water.”