The length of a precision part is 2 mm. If it is drawn on a part drawing with a scale of 20:1, how many centimeters should the length be drawn?
一种精密零件的长是2毫米，把它画在比例尺是20：1的零件图上，长应画多少厘米．
<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>