On a drawing with a scale of 50:1, the measured length of a part is 20 cm, what is its actual length in cm?
在比例尺是50：1的图纸上，量的某零件的长是20厘米，它的实际长度是多少厘米．
<gadget id="calculator">50 / 1</gadget>
<output>50</output>

<gadget id="calculator">20 / 50</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>