56 children lined up to go on a spring outing. From the top of the line, Xiao Gang was the 19th, and from the bottom of the line, Xiao Li was the 12th. How many classmates are there between Xiaogang and Xiaoli?
56个小朋友排成一队去春游，从排头数，小刚是第19个，从排尾数，小莉是第12个．小刚与小莉中间有多少个同学．
<gadget id="calculator">19 + 12</gadget>
<output>31</output>

<gadget id="calculator">56 - 31</gadget>
<output>25</output>

<result>25</result>