To achieve the sum of the pair dices =2; each dice should give 1.
The first dice numbers are 1,2,3,4,5,6
The probability of getting 1 with the first dice =1/6
The second dice numbers are 1,2,3,4,5,6
The probability of getting 1 with the second dice=1/6
The probability that the sum of both numbers is 2 where first and second dices are equal 1=Probability of 1 on first dice × probability of 1 on second dice=1/6 ×1/6=1/36.