Xiaohua has 300 stamps, Xiaoming has 40 stamps twice as many as Xiaohua, Xiaoqiang is half of the sum of Xiaoming and Xiaohua, how many stamps does Xiaoqiang have?
小华有邮票300张，小明比小华的2倍多40张，小强是小明、小华之和的一半，小强有多少张邮票？
<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<gadget id="calculator">600 + 40</gadget>
<output>640</output>

<gadget id="calculator">640 + 300</gadget>
<output>940</output>

<gadget id="calculator">940 / 2</gadget>
<output>470</output>

<result>470</result>