The surface of the football is surrounded by several black pentagons and white hexagons. There are 12 black pieces and how many white pieces?
足球的表面是由若干黑色五边形和白色六边形皮块围成的，黑色皮有12块，白色皮有多少块？
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>