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",“Why aren’t you expensive A hundred catties for just three coins, and once winter arrives, they will sell for five coins.” The old man sighed: “Don’t think my bricks are expensive either; my family only earns a hard-earned living.”,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."。