Make a small fortune.
Used to show that someone is doing things quickly: three times five divided by two.
Used when two people share things equally: half a catty and eight liang, 2 1 plus 5.
Use when it is really impossible to change: say nothing.
It shows that you are not thoughtful in doing things, and you can use it when you do it: two things can't be done, and you can't care.