10 children play 3 sets of chess for 4 hours, how many hours do they play on average?
10个小朋友玩儿3副象棋，玩了4个小时，平均每人玩多少个小时．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">6 * (2/5)</gadget>
<output>12/5 = around 2.4</output>

<result>12/5 = around 2.4</result>