A warehouse has 204 tons of flour, and 15 trucks were transported yesterday. If each truck transports a ton, how many tons of flour are left in this warehouse.
一个仓库有面粉204吨，昨天运走了15车，如果每车运a吨，这个仓库还剩多少吨面粉．
<gadget id="calculator">204 - 15</gadget>
<output>189</output>

<result>189</result>