Eight to ten crabs per catty are called one or two crabs, that is, 1 catty has 8- 10 crabs;
A catty of five to seven crabs is called one and a half crabs, that is, 1 catty of one and a half crabs has 5-7 crabs;
Four to five crabs per catty are called Eriocheir sinensis, that is, 1 catty Eriocheir sinensis has 4-5 crabs;
A catty of three or four crabs is called two and a half crabs, that is to say, there are three or four crabs in a catty.
One catty is called three or two crabs, and one catty is called half a catty of crabs, both of which are biennial; The six-two, seven-two, eight-two and nine-two crabs are all three-year-old crabs.