Some Go pieces, white and black are arranged in the order of 3 white, 5 black, 3 white, 5 black, .... There are 60 white chess pieces, how many black chess pieces are at least?
一些围棋子，白棋和黑棋按照3白、5黑、3白、5黑、…这样的顺序排列．白棋共有60枚，黑棋最少有多少枚？
<gadget id="calculator">60 / 3</gadget>
<output>20</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>