There are 568 boys and 557 girls in Guangming Primary School. 246 people signed up for the sports meeting. How many people did not sign up?
光明小学男生有568人，女生557人，报名参加运动会的有246人，没有报名的有多少人？
<gadget id="calculator">557 - 246</gadget>
<output>311</output>

<gadget id="calculator">568 + 311</gadget>
<output>879</output>

<result>879</result>