There are 405 tourists in the amusement park in the morning, 150 people leave at noon, and another 150 people come in the afternoon. How many tourists are there in the amusement park at this time?
游乐园上午有游客405人，中午有150人离去，下午又来了150人，这时游乐场有多少游客？
<gadget id="calculator">405 - 150</gadget>
<output>255</output>

<gadget id="calculator">255 + 150</gadget>
<output>405</output>

<result>405</result>