A number can be proportional to 3, 4, 5, what is the largest number.
一个数能与3，4，5组成比例，这个数最大是多少．
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">20 / 3</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>