A salted fishapos;s

The old man said, "It depends on how many houses you want to build. Six houses would cost about 40,000, three houses around 20,000. How many houses are you planning to build",Someone asked, "Yan Er, are there still many stones like this in the quarry",He pulled out another thin slate and showed it to everyone: "There are also these kinds. The foreman at the quarry said that these slates can be used for heating floors."。