You can write an equation to represent this situation. Let x represent the number of girls.
283 = x + (x + 27)
Here, we are adding the number of girls with 27 more people than this amount of girls. This will allow us to add the number of girls, x, with the number of boys, x + 27, to get a total of 283.
This equation can be simplified if we add the like terms together: the x's.
So,
283 = 2x + 27.
Since this is a multi-step equation, we must use the reversed order of operations; undo addition first.
283 - 27 = 2x + 27 - 27
256 = 2x + 0
256 = 2x
Now, we must undo multiplication by dividing.
256/2 = 2x/2
128 = 1x
So, x, the number of girls, is equal to 128.
Hope this helps you! :)