There were 742 tourists in the science and technology park in the morning, 265 people left at noon, and 306 tourists came in the afternoon. How many tourists were there in the park at this time?
科技园上午有游客742人，中午有265人离去，下午又来了306位游客，这时园内有多少游客？
<gadget id="calculator">742 - 265</gadget>
<output>477</output>

<gadget id="calculator">477 + 306</gadget>
<output>783</output>

<result>783</result>