The surface of a football is surrounded by 32 black pentagons and white hexagons. The ratio of the number of pieces of black leather to white leather is 3:5, how many pieces of black leather are there?
一个足球的表面是由32块黑色五边形和白色六边形围成的．黑色皮和白色皮的块数的比是3：5，黑色皮有多少块？
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">32 * (3/8)</gadget>
<output>12</output>

<result>12</result>