You can check it here. This is the spot foreign exchange rate of Industrial and Commercial Bank of China:

/other/quotation.jsp

According to today's foreign exchange rate, 100 won can be converted into RMB: 6.4774 yuan (cash purchase price).

So today 4000 yen can be converted into RMB: 4000/100× 6.4774 = 259.10 yuan.