The school allocates a sum of money to buy sporting goods. If you use it to buy footballs, you can buy 100 of them, and if you buy basketballs, you can buy 80 of them. If you buy 20 footballs first, and buy basketballs with the remaining money, how many basketballs can you buy?
学校拨了一笔钱买体育用品，如果用它买足球可以买100个，买篮球可以买80个．如果先买20个足球，剩下的钱再买篮球，可以买篮球多少个．
<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">100 / 80</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">80 / (5/4)</gadget>
<output>64</output>

<result>64</result>