A typist wants to type a manuscript, and has already typed 300 pages, leaving 25% of the total pages untyped. How many pages does this manuscript have?
打字员要打一份书稿，已经打了300页，还剩下总页数的25%没有打．这份书稿一共有多少页？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">300 / (3/4)</gadget>
<output>400</output>

<result>400</result>