The big-faced cat caught some fish, but the blue-skinned mouse stole 60% of them because of carelessness. It counted the remaining fish and found that there were only 30 fish. How many fish were stolen by the blue-skinned mouse? ．
大脸猫抓到了一些鱼，却因为看管不慎，被蓝皮鼠偷走了60%，它数了数剩下的鱼，发现只有30条了，那么被蓝皮鼠偷走了多少条鱼．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 / (2/5)</gadget>
<output>75</output>

<gadget id="calculator">75 * (3/5)</gadget>
<output>45</output>

<result>45</result>