Dongfeng Machine Tool Factory produced 420 machine tools in April, an increase of (1/5) compared to March. How many machine tools were produced in March?
东风机床厂四月份生产机床420台，比三月份增产(1/5)．三月份生产机床多少台？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">420 / (6/5)</gadget>
<output>350</output>

<result>350</result>