The school gymnasium loaned out 320 balls, and the number of remaining balls was twice as many. How many balls are there in the sports room?
学校体育室借出了320只皮球，剩下皮球只数是借出的2倍．体育室原有多少只皮球？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">320 * 3</gadget>
<output>960</output>

<result>960</result>