Buying or selling a Cram school

Hi,

Moderator, please feel free to redirect me to another forum or if this topic had been covered, to direct me.

Any tips on appreciating an existing school. In other words I want to buy or sell.

Is there a formula to give one a quick starting point as to the value of the core business (say English Cram School)
eg. turnover per year x 2.5

I guess this formula would differ slightly for schools in the north and south.

Thank you,

Jáco