combs

pls help with the following qs (idk where to even start) 1. How many selections of at least one object can be made from n distinct objects? 2. Recall that a digit sum of a number n is the value obtained when the digits of n are added together. For example, the digit sum of...

i actually dont know anything about perms and combs and i have a exam which has it. in literally 3 weeks. ive watched a thousand youtube videos but its so conceptually hard to get cause there arent many formulas that idek where to start. i look at my textbook and be like WTAF is going on. how do...