From March 28 to April 5, Wang Xiaogang wrote a total of 180 big characters. How many big characters does he write on average every day?
王小刚从3月28日到4月5日，共写了180个大字，他平均每天写多少个大字．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">180 / 9</gadget>
<output>20</output>

<result>20</result>