My iPod touch keeps crashing while playing a game

I downloaded recently Dinner Dash Rush and in the beginning it was fine, playing the time I wanted but in these last few days I start playing the game and suddenly it crashes. I have tried turning the ipod off and on but after like the second time playing the game it goes back to crashing. What should I do?. Also, the facebook app crashes A LOT, since the last update. I don't have the IOS 7 because my ipod is the 4th generation and I didn't get to have the update.