A piece of iron wire can just enclose a square with a side length of 4 cm. If this wire is used to enclose a rectangle, its length is 5 cm and its width is in cm.
一根铁丝正好能围成一个边长是4厘米的正方形，如果用这根铁丝围一个长方形，长是5厘米，宽是多少厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 - 5</gadget>
<output>3</output>

<result>3</result>