61 students lined up in a line, after counting, leave the line from the 13th to the 25th, how many people are still in the line.
61个同学排成一行，报数后，13号到25号离开队伍，队伍里还有多少人．
<gadget id="calculator">25 - 13</gadget>
<output>12</output>

<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<gadget id="calculator">61 - 13</gadget>
<output>48</output>

<result>48</result>