Pairwise combination, first choose the coin of 1 yuan, and then find a match. There are three ways. 1 yuan 50, 1 yuan 1 angle, 1 yuan 5 points.

Let's take 50 cents. Only 50 cents and 1 cents, 50 cents and 5 points can match.

Finally, choose a coin with 1 minute, and only 1 minute and 5 cents match it.

So there are six kinds.