The students participated in the Science and Technology Museum. 243 students went to the fourth grade, 199 students went to the fifth grade, and 257 students went to the sixth grade. How many people went to the three grades?
同学们参加科技馆，四年级去了243人，五年级去了199人，六年级去了257人，三个年级一共去了多少人？
<gadget id="calculator">243 + 199 + 257</gadget>
<output>699</output>

<result>699</result>