Let S be the sum of the outcomes of two dice rolls. The total number of outcomes is 36. The outcomes where S < 7 are: (1,1), (1,2), (1,3), (1,4), (1,5), (2,1), (2,2), (2,3), (2,4), (3,1), (3,2), (3,3), (4,1), (4,2), (5,1). There are 15 such outcomes.