An electronic part is 4mm long, draw it on the drawing with a scale of 7:1, how many millimeters should be drawn.
一个电子零件长4毫米，用7：1的比例尺把它画在图纸上，应画多少毫米．
<gadget id="calculator">7 / 1</gadget>
<output>7</output>

<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<result>28</result>