The school buys a batch of books, among which story books account for 50%, and comic books account for 30%. Story books are 200 more than comic books. How many books did the school buy in total?
学校买一批书，其中故事书占50%，连环画占30%，故事书比连环画多200本，学校共买了多少本书？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 / (1/5)</gadget>
<output>1_000</output>

<result>1_000</result>