There are 45 students in Class 1, 22 of them are in the chorus group, and 24 are in the dance group. How many people are in both the chorus group and the dance group?
四1班有学生45人，有22人参加合唱小组，24人参加舞蹈小组，既参加了合唱小组又参加了舞蹈小组的有多少人．
<gadget id="calculator">24 - 45</gadget>
<output>-21</output>

<gadget id="calculator">22 + (-21)</gadget>
<output>1</output>

<result>1</result>