The school shipped 12 packs of story books, each with 25 books, and distributed these story books to the fourth, fifth, and sixth grades according to the ratio of 1:2:3. How many books were distributed to the sixth grade?
学校运来12包故事书，每包25本，把这些故事书按1：2：3分给四、五、六年级，六年级分到多少本？
<gadget id="calculator">25 * 12</gadget>
<output>300</output>

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

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

<gadget id="calculator">300 * (1/2)</gadget>
<output>150</output>

<result>150</result>