Uncle Liu wants to process a metal storage box with a length of 4 meters, a width of 1.2 meters and a height of 2.5 meters. Now there are angle irons on each side. How many meters of angle irons are needed for this storage box?
刘大伯要加工一个长4米、宽1.2米、高2.5米的铁皮储物箱，现在各边都安上角铁，这个储物箱需要多少米角铁？
<gadget id="calculator">4 + 1.2 + 2.5</gadget>
<output>7.7</output>

<gadget id="calculator">7.7 * 4</gadget>
<output>30.8</output>

<result>30.8</result>