Rounding Numbers before Socket.io emit?

I'm using Nodejs with Socket.io.

I want to minimize the size of the data I'm sending. I want to send numbers to the client. My numbers have great precision but the client only need to know the first few digits of the numbers.

Will rounding numbers decrease the size of the data I'm sending (with Socket.io)? With JSON.stringify, doing so would work but I don't know if Socket.io serialize/parser works the same way.

And/or is there another more efficient way to do so?