Not getting this question

#1

I have no idea what to do with this question?

#2

the question is about computing factorial of large numbers like how will you compute 100! as you can’t store factorial of these big numbers in any data type.
so one idea to approach this problem can be:
1.create an array of size 1500 :since max possible number is 500! so digits that can be maximally used in the solution can be 1000^500 = 1500
2.now try to represent factorial as an array. like if x = 1500, array representation is: {1,5,0,0}
now figure out yourself how to multiply a number in this representation.

Thanks.