An old cow eats 20 catties of grass a day, and two lambs eat 10 catties of grass for two days. The food intake of the lambs is the same as that of the old cows.
一头老牛一天吃20斤草，2只小羊两天吃10斤草，小羊的食量是老牛的多少．
<gadget id="calculator">10 / 2 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) / 20</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>