Shaw School will hold the 2nd Campus Reading Festival next week. The school will purchase 900 science books, literature books, and story books according to the ratio of 2:1:3 according to the needs, including how many story books.
逸夫学校下周举行第二届校园读书节，学校根据需要，按2：1：3购进科技书、文艺书、故事书共900本，其中故事书多少本．
<gadget id="calculator">2 + 1 + 3</gadget>
<output>6</output>

<gadget id="calculator">3 / 6</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">900 * (1/2)</gadget>
<output>450</output>

<result>450</result>