First thanks, I was going in completely wrong direction and thinking it was way more complicated.. But why multiply by 100k? the formula basically looks like N

First thanks, I was going in completely wrong direction and thinking it was way more complicated.. But why multiply by 100k? the formula basically looks like NumOfVaxedPplSickPer100k * 100k / TotalVaxedPopulation Is multiplying to 100k an arbitrary choice? If not then what does (NumOfVaxedPplSickPer100k * 100k) give you?