Xiaoming's family bought a cuboid mattress, 2 meters long, 1.5 meters wide, and 20 centimeters thick. The outer layer of the mattress was wrapped with cloth. Dad asked Xiao Ming: "How many square meters of cloth do you need to cover this mattress?" Xiao Ming couldn't figure it out for a while, so please help Xiao Ming answer it smartly. (The interface part is ignored)
小明家买来了有一张长方体床垫，长2米宽1.5米厚20厘米，床垫外层是用布包封的．爸爸考小明："包封这张床垫需多少平方米的布？"小明一时算不出来，请聪明的你帮小明解答．(接口部分忽略不计)
<gadget id="calculator">2 * 1.5</gadget>
<output>3</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 * (1/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1.5 * (1/5)</gadget>
<output>0.3</output>

<gadget id="calculator">3 + (2/5) + 0.3</gadget>
<output>3.7</output>

<gadget id="calculator">3.7 * 2</gadget>
<output>7.4</output>

<result>7.4</result>