There are 420 stalls in the farmer's market, 120 more than before the expansion. After the expansion, how many percent has the booth increased compared to before the expansion?
农贸市场现有摊位420个，比扩建前增加120个．扩建后摊位比扩建前增加了百分之几？
<gadget id="calculator">420 - 120</gadget>
<output>300</output>

<gadget id="calculator">120 / 300</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>