Xiao Ming typed a 2400-word article, and he has already typed some, but there are still 280 characters left to type. How many words did Xiao Ming type?
小明打一篇2400字的文章，已经打了一些，还剩280字没打．小明打了多少字？
<gadget id="calculator">2_400 - 280</gadget>
<output>2_120</output>

<result>2_120</result>