The padded garment factory needs to make 680 pieces of cotton padded clothes for children, 187 pieces were made on the first day, and 213 pieces were made on the second day. How many pieces are left unfinished?
棉服厂要做680件儿童棉衣，第1天做了187件，第2天做了213件，还有多少件没有做？
<gadget id="calculator">187 + 213</gadget>
<output>400</output>

<gadget id="calculator">680 - 400</gadget>
<output>280</output>

<result>280</result>