Teacher Zhang went to the street to buy some sporting goods, and the money he brought was just enough to buy 12 basketballs or 18 footballs. He first bought 4 basketballs, and the rest of the money was spent on footballs. How many footballs can you buy with the rest of the money?
张老师到街上去买一些体育用品，他带的钱正好够买12个篮球或18个足球．他先买了4个篮球，剩下的钱全部买足球．剩下的钱还可以买多少个足球？
<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<result>12</result>