Xiaofang has already typed 1,600 words in an article, exactly 40% of the full text, how many words are left?
小芳打一篇文章，已经打了1600个字，正好打了全文的40%，还有多少字没有打？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1_600 / (2/5)</gadget>
<output>4_000</output>

<result>4_000</result>