The school has 630 books, according to 2:3:4, the third, fourth, and fifth grades are borrowed, and how many books are borrowed in the fifth grade.
学校有图书630本，按2：3：4借出三、四、五三个年级，五年级借到图书多少本．
<gadget id="calculator">2 + 3 + 4</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">630 * (4/9)</gadget>
<output>280</output>

<result>280</result>