There were 45 British children who came to the Experimental Primary School to participate in the "Hand in Hand" social activity. Among them, 32 could understand Chinese and 40 could understand English. How many people know both Chinese and English?
有45名英国小朋友来实验小学参加"手拉手"联谊活动，其中有32懂汉语，40人懂英语．既懂汉语又懂英语的有多少人？
<gadget id="calculator">40 - 45</gadget>
<output>-5</output>

<gadget id="calculator">32 + (-5)</gadget>
<output>27</output>

<result>27</result>