The school buys 8 footballs and 8 basketballs each. It costs 576 yuan to buy a football and 720 yuan to buy a basketball. How much is a football cheaper than a basketball? (answer in two ways)
学校买回足球、篮球各8个，买足球用去576元，买篮球用去720元，一足球个比一个篮球便宜多少元？(用两种方法解答)
<gadget id="calculator">720 / 8</gadget>
<output>90</output>

<gadget id="calculator">576 / 8</gadget>
<output>72</output>

<gadget id="calculator">90 - 72</gadget>
<output>18</output>

<result>18</result>