A shopping mall: 6 pieces per box, 200 yuan per box; B shopping mall: 2 pieces, 70 yuan; C shopping mall: 40 yuan each. This is the price of the same basketball in three shopping malls. The school needs to buy 12 basketballs of this kind. How can I buy the most economically? How much is the minimum?
A商场：每箱6个，每箱200元；B商场：2个70元；C商场：每个40元．这是同一种篮球在三个商场的价钱，学校要买12个这种篮球，怎样买最省钱？最少要多少钱？
<gadget id="calculator">12 / 6</gadget>
<output>2</output>

<gadget id="calculator">200 * 2</gadget>
<output>400</output>

<result>400</result>