There are 8 butterflies and twice as many dragonflies as butterflies. How many dragonflies are there?
蝴蝶有8只，蜻蜓的只数是蝴蝶的2倍，蜻蜓有多少只．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>