The sum of four consecutive even numbers is 2004, what is the largest number among them?
四个连续偶数之和是2004，那么其中最大的数是多少．
<gadget id="calculator">2 * 249</gadget>
<output>498</output>

<gadget id="calculator">498 + 6</gadget>
<output>504</output>

<result>504</result>