Dongfeng Machine Tool Factory produced 400 machine tools in April, an increase of (1/4) in May compared to April. How many machine tools were produced in May?
东风机床厂四月份生产机床400台，五月份比四月份增(1/4)，五月份生产机床多少台？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">400 * (5/4)</gadget>
<output>500</output>

<result>500</result>