Hey all you math people out there.

I'm looking for lesson plans on mean, median, mode, and range that can be adapted to first grade. Our school didn't do real well on these particular subjects on the third grade math assessment, so our task is to find new ways to teach these. Since these are not actually in our first grade curriculum, I'm looking for those of you with expertise in that area. Our principal is hoping that all of our 1st, 2nd, 3rd grade can hit those areas really hard to bring up those scores this year. Any ideas?