However, it's known that any multinomial coefficient can be expressed as the product of a sequence of related binomial coefficients. Express the multinomial coefficient 10M{2,3,5} as a product of binomial coefficients. Hint: the first one is 10C2. 
Give a general formula for calculating the multinomial coefficient nM{a,b,c,d}, where a+b+c+d=n.
Give a general formula for calculating the multinomial coefficient nM{a,b,c,d}, where a+b+c+d=n.