There were 945 tourists in Tianhe Park in the morning, 518 left at noon, and 402 tourists came in the afternoon. How many tourists are there in the park at this time?
天河公园上午有游客945位，中午有518位离去，下午又来了402位游客，这时园内有多少位游客？
<gadget id="calculator">945 - 518</gadget>
<output>427</output>

<gadget id="calculator">427 + 402</gadget>
<output>829</output>

<result>829</result>