Class 4 and Class 1 of a certain school have a physical education class on the playground, and the whole class is lined up in a row. When counting from left to right, Xiao Ming Bao’s number is 21; when counting from right to left, Xiao Ming Bao’s number is 25. How many people are there in this class?
某校四1班在操场上体育课，全班排成一列横队．从左向右报数，小明报的数是21；从右向左报数，小明报的是25．这个班共有多少人．
<gadget id="calculator">25 - 1</gadget>
<output>24</output>

<gadget id="calculator">21 + 24</gadget>
<output>45</output>

<result>45</result>