The students went to visit the observatory. In the morning, there were 3 batches of students to visit, with 69 students in each batch. There were 213 students visiting in the afternoon. How many students visited this day?
同学们去天文台参观，上午有3批学生去参观，每批有69人．下午参观的学生有213人，这一天一共有多少学生去参观？
<gadget id="calculator">69 * 3</gadget>
<output>207</output>

<gadget id="calculator">207 + 213</gadget>
<output>420</output>

<result>420</result>