Uncle Li from the oil mill told Xiaojing: "2 tons of rapeseed can squeeze out 840kg of rapeseed oil." What is the oil yield of these rapeseeds?
榨油厂的李叔叔告诉小静："2吨油菜籽能榨出菜油油840kg．"这些油菜籽的出油率是多少？
<gadget id="calculator">2 * 1_000</gadget>
<output>2_000</output>

<gadget id="calculator">840 / 2_000</gadget>
<output>21/50 = around 0.42</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(21/50) * 1</gadget>
<output>21/50 = around 0.42</output>

<result>21/50 = around 0.42</result>