What's the count?

Refers to odd numbers and even numbers or even numbers.

Fine number, a "Yu Fu", refers to the algorithm of even or even numbers. "Fine" is a fixed whole after equal division; However, if it is divided from a certain cardinal number in a way that is more than or equal to 2 times but less than 3 times, it is called "coarse", that is, "folded in half". In addition, in some ancient divination in China, there are also examples of using specific division operations to get detailed figures.