There are two bookshelves, A and B. There are 600 books in A bookshelf. After borrowing (1/3) from A bookshelf and borrowing (3/4) from B bookshelf, there are 100 more books on A bookshelf than B bookshelf. ． How many books are there on shelf B?
甲乙两个书架，甲书架，有600本书，从甲书架借出(1/3)，乙书架借出(3/4)以后，甲书架上的书比乙书架的2倍还多100本．乙书架原来有多少本书？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">600 * (2/3)</gadget>
<output>400</output>

<gadget id="calculator">400 - 100</gadget>
<output>300</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">300 / 2 / (1/4)</gadget>
<output>600</output>

<result>600</result>