A rectangle with a length of 38 cm is used to form a rectangle. If the length is 15 cm, what is the width in cm?
用一根长38厘米的铁丝围成一个长方形，若长为15厘米，宽为多少厘米．
<gadget id="calculator">38 / 2</gadget>
<output>19</output>

<gadget id="calculator">19 - 15</gadget>
<output>4</output>

<result>4</result>