Respuesta :
so there were 21 students from the start then 4 new people joined so 21 plus 4 equals 25 . 25 minus 2 equals 23 23 minus 1 equals 22
You start with 21 then add 2 as 2 moved away
21+2=23
1 student was transferred add that on
23+1=24
At the begging of the year there were 24 students.