Xiao Ming borrowed a comic book, if he reads 16 pages every day, it will take 15 days to finish it. How many days will it take if you read 4 fewer pages a day?
小明借了一本漫画书，如果每天看16页，需要15天才能能看完．如果每天少看4页，需要多少天看完？
<gadget id="calculator">16 * 15</gadget>
<output>240</output>

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<gadget id="calculator">240 / 12</gadget>
<output>20</output>

<result>20</result>