912 tourists came to the zoo in the morning, 278 left at noon, and 455 came in the afternoon. How many tourists are there in the zoo at this time?
动物园里上午来了912个游客，中午走了278个，下午又来了455个，这时动物园里有多少个游客？
<gadget id="calculator">912 - 278</gadget>
<output>634</output>

<gadget id="calculator">634 + 455</gadget>
<output>1_089</output>

<result>1_089</result>