If you bought 55 footballs and bought 20% less basketballs than footballs, how many basketballs did you buy?
买来足球55个，买来的篮球比足球少20%，买来篮球多少个？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">55 * (4/5)</gadget>
<output>44</output>

<result>44</result>