The way to turn ballots into results is just a simple division, numerator (sum of scores) over denominator (number of voters). Try to explain to me the function

The way to turn ballots into results is just a simple division, numerator (sum of scores) over denominator (number of voters). Try to explain to me the function from ballots to results in IRV with 5 candidates in as simple of terms? It's absolutely much harder to analyze IRV and predict what is going to happen. In every range voting scenario, I can show you a bunch of ballots and you could quickly figure out the smallest change required to make a different person win. With IRV, I imagine you'd first start by drawing a big tree of options, and then simulating every way each could play out...