Xiao Ming prints an article. After typing 1600 words, 60% of the full text remains untyped. How many words are there in this article?
小明打印一篇文章，打了1600个字后，还剩全文的60%没打，这篇文章有多少个字？
<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">1_600 / (2/5)</gadget>
<output>4_000</output>

<result>4_000</result>