This video lecture from Permutation, Combination and Probability (F.Sc. first year Mathematics) covers: Question numbers 1-2 of exercise 7.1. In these questions we find factorial of given notations and convert the given expressions in factorial form. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.