1 banana can be exchanged for 3 apples, 1 apple can be exchanged for 2 pears, and 3 bananas can be exchanged for how many pears.
1只香蕉能换3只苹果，1个苹果能换2个梨，3个香蕉能换多少个梨．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<result>18</result>