The Xing Neighborhood Committee wanted to paint a courtyard wall 20 meters long and 3 meters wide, and a 12-square-meter publicity window on the wall. Please do the math, how big is the painted area?
星居委会要粉刷一个长20米、宽3米的院墙，墙上一块面积12平方米的宣传橱窗．请你算一算，粉刷的面积有多大？
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">60 - 12</gadget>
<output>48</output>

<result>48</result>