The price of a basketball is 150 yuan, and the mall is now holding a campaign: buy two get one free. The school buys 2 basketballs at a time, how much is each basketball cheaper?
一条篮球的价钱是150元，商场现在搞活动：买二送一．学校一次性买2个篮球，每个篮球便宜多少钱？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">150 / 3</gadget>
<output>50</output>

<gadget id="calculator">2 * 50</gadget>
<output>100</output>

<gadget id="calculator">150 - 100</gadget>
<output>50</output>

<result>50</result>