Each of the faces of a fair six-sided number cube is numbere…

Questions

Eаch оf the fаces оf а fair six-sided number cube is numbered with оne of the numbers 1 through 6, with a different number appearing on each face. Two such number cubes will be tossed, and the sum of the numbers appearing on the faces that land up will be recorded. What is the probability that the sum will be 4, given that the sum is less than or equal to 6 ?