There are 364 boys and 287 girls in the third grade, and 396 have their height measured. How many people have not measured their height?
三年级男生有364人，女生有287人，已经量了身高的有396人，还有多少人没有量身高？
<gadget id="calculator">287 - 396</gadget>
<output>-109</output>

<gadget id="calculator">364 + (-109)</gadget>
<output>255</output>

<result>255</result>