If there are 25 students and she wants either 3,4,5 equal teams you simply take and divide 25 by the numbers and determine if they are equal teams or not. So dividing 25 by 3 and getting 8.3 repeating isn't an equal team which means she cant have only 3 teams. Or you can divide 25 by 4 which will give you 5 students to a group which is an equal team set through out the room, also you can divide 25 by 5 which gives you 4 students to a group which also is an equal team set through out the room. Therefore the numbers of groups she can have are 4 and 5 but 3 is out of the question because it is a decimal also another thing about it is that it's an irrational number.
