30 people line up in a line, the 25th person from left to right is Xiaohong, and the 25th person from right to left is Xiaohua, how many people are there between Xiaohong and Xiaohua?
30人排成一队，从左向右数第25人是小红，从右向左数第25人是小华，小红和小华之间有多少人？
<gadget id="calculator">25 - 30 - 2</gadget>
<output>-7</output>

<gadget id="calculator">25 + (-7)</gadget>
<output>18</output>

<result>18</result>