Xiao Ming practiced calligraphy at home in February this year, and wrote 30 characters a day. How many characters did he write in total this month?
小明今年二月份在家练字，每天写30个，这个月一共写了多少个字．
<gadget id="calculator">30 * 28</gadget>
<output>840</output>

<result>840</result>