There is a pasture with 30 sheep, which is less than the number of cattle (2/5). How many cattle are there in this pasture?
有一个牧场，养了30只羊，比牛的数量少(2/5)，这个牧场养牛多少只？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 / (3/5)</gadget>
<output>50</output>

<result>50</result>