Both Li Gang and Wang Hong are reading the book "Fairy Tales", which has 120 pages in total. Li Gang reads 12 pages a day, and Wang Hong reads 15 pages a day. Wang Hong watched it a few days earlier than Li Gang?
李刚和王红都在看《童话故事》这本书，全书共有120页．李刚每天看12页，王红每天看15页．王红比李刚提前几天看完？
<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<gadget id="calculator">120 / 15</gadget>
<output>8</output>

<gadget id="calculator">10 - 8</gadget>
<output>2</output>

<result>2</result>