To produce a batch of computers, the planned (3/5) has been produced, and there are still 420 unproduced, how many have been produced?
生产一批电脑，已经生产了计划的(3/5)，还有420台未生产，已经生产了多少台？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">420 / (2/5)</gadget>
<output>1_050</output>

<gadget id="calculator">1_050 - 420</gadget>
<output>630</output>

<result>630</result>