Math - What's the Decade?

Yesterday in my 2nd grade math class, I introduced the concept of rounding to the nearsted ten.  I was suprised how confused many of the students were, even while using a number line.  I woke up at 4:45 this morning with an idea: a game to practice rounding.  This is what I came up with:

The first student draws two cards from a deck, and makes a two digit number.  They then write that number down, as well as the nearest decade number, ten, to practice their rounding skills.  The students played with a partner, and I found that the peer support they received while practicing made a huge difference.  Each student had their own worksheet, but they wrote down both player's numbers.  The kids had fun and did not want to stop.  I think I will use this for a math warm-up activiity once in a while to keep skills sharp.  This game could also be played with dice, or by drawing three cards.

You can download the free worksheet here