In multiplication, if one factor is multiplied by 3 and the other factor is multiplied by 5, how many times the product is multiplied.
在乘法里，一个因数扩大3倍，另一个因数扩大5倍，积扩大多少倍．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>