The sports group has a basket of balls, of which footballs account for 45%. If 5 more basketballs are put in, footballs only account for 36%. Then, how many footballs are there in this basket?
体育组有一筐球，其中足球占45%，如果再放入5个篮球，足球就只占36%，那么，这筐球中，足球有多少个．
<gadget id="calculator">36 / 100</gadget>
<output>9/25 = around 0.36</output>

<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">(9/25) / (9/20)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 / (1/5)</gadget>
<output>25</output>

<gadget id="calculator">25 * (9/25)</gadget>
<output>9</output>

<result>9</result>