The sum of three consecutive even numbers is 78, what is the largest even number among them?
三个连续偶数的和是78，其中最大的那个偶数是多少．
<gadget id="calculator">78 / 3</gadget>
<output>26</output>

<gadget id="calculator">26 + 2</gadget>
<output>28</output>

<result>28</result>