A blue whale is 15m long, and the length of its head accounts for about (2/5) of it. How long is the head of this blue whale?
一头蓝鲸长15m，其是头部的长度约占它的(2/5)．这头蓝鲸的头部长多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">15 * (2/5)</gadget>
<output>6</output>

<result>6</result>