There are 1,800 students in the fourth, fifth and sixth grades of the Experimental Primary School, 576 students in the fourth grade, and 624 students in the fifth grade. How many people are in the sixth grade?
实验小学四，五，六年级共有1800人，四年级有576人，5年级有624人．六年级有多少人？
<gadget id="calculator">576 + 624</gadget>
<output>1_200</output>

<gadget id="calculator">1_800 - 1_200</gadget>
<output>600</output>

<result>600</result>