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",Then he told Yan Lao Er, "I'll calculate half the amount for you first. When you return from the quarry, tell me the exact number.",Who can carry dozens of dollars out, mustn't drown.。