一个新发现的数学公式：

来源: 于 2025-09-05 22:47:36 [旧帖] [给我悄悄话] 本文已被阅读：次

x% of y = y% of x So, in order to calculate a percentage in your head it might be easier to turn it around. What is 4% of 50? It's the same as 50% of 4.