The Xinhua mobile phone shop has bought a batch of mobile phones, 60% of which have been sold this month, and the remaining ones are 400 less than what has been sold. How many phones are there in total?
新华手机店进了一批手机，本月已卖这批手机的60%，剩下的比已卖的少400部．这批手机共有多少部？
<gadget id="calculator">60 / 100</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">(3/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">400 / (1/5)</gadget>
<output>2_000</output>

<result>2_000</result>