The youngest rock is 3, cross cutting tells that the rock is younger because it is younger then the one its cutting threw. the next one is 1, it is the 2nd youngest because it is on top of all the other layers. 6 is the 3rd youngest because it is under 1. then 2 would be the 4th youngest because it cuts threw the 4 and 5. then five would be next because it is on top of the 2 and the 4. then 2 would be the oldest because it is on the bottom of all of them.