When two factors are multiplied, one factor is multiplied by 2, and the other factor is multiplied by 4, then the product is multiplied by how many times.
两个因数相乘，一个因数扩大2倍，另一个因数扩大4倍，则积扩大多少倍．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<result>8</result>