Oscar Cunningham on Nostr: I've heard a/b ≤ c/d → a/b ≤ (a+c)/(b+d) ≤ c/d referred to as the 'Batting ...

I've heard
a/b ≤ c/d → a/b ≤ (a+c)/(b+d) ≤ c/d
referred to as the 'Batting Average Lemma', which I'm sure makes sense if you're American. Like if you succeed in a out of b attempts and then your performance improves to c out of d, then your overall performance has to be between the two.