The school originally had 20 basketballs and footballs, the ratio of basketballs to footballs was 7:3, and some basketballs were bought, and the ratio of basketballs to the total was 4:5, how many more basketballs were bought?
学校原有篮球、足球共20个，篮球与足球之比是7：3，又买来一些篮球，这时篮球与总数之比是4：5，又买来篮球多少个？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 20</gadget>
<output>16</output>

<gadget id="calculator">7 + 3</gadget>
<output>10</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">2 * 7</gadget>
<output>14</output>

<gadget id="calculator">16 - 14</gadget>
<output>2</output>

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

<gadget id="calculator">2 / (1/5)</gadget>
<output>10</output>

<result>10</result>