There are 35 basketballs and footballs, of which footballs account for (2/5). Later, several footballs are bought, so that the number of basketballs and footballs is equal. How many footballs were bought later?
篮球和足球共35个，其中足球占(2/5)，后来又买来若干个足球，这样篮球与足球的个数相等，后来买了多少个足球？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">35 * (2/5)</gadget>
<output>14</output>

<gadget id="calculator">35 - 14</gadget>
<output>21</output>

<gadget id="calculator">21 - 14</gadget>
<output>7</output>

<result>7</result>