Wang Dong can read a storybook in 10 days, but Wang Hong can finish it in 4 days longer than Wang Dong, and Wang Dong can read 12 pages more than Wang Hong every day, so how many pages does the storybook have?
一本故事书，王东10天可以看完，而王红要比王东多4天看完，王东每天比王红多看12页，那么这本故事书共有多少页．
<gadget id="calculator">10 / 4</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">10 + 4</gadget>
<output>14</output>

<gadget id="calculator">12 * (5/2) * 14</gadget>
<output>420</output>

<result>420</result>