Hello There!
As for this problem, we would have to set up an equation in order to determine the missing age. We would do this because we want to find the missing age and by setting up an equation it will help find the age easier, as opposed to manually calculating it. With that said, let's begin to solve.
First, we would create an equation based on what the question says, which would look as:
x + x + 2 = 12
2x + 2 = 12
Subtract two from both sides.
2x = 10
The grand daughter is 5 years old and since the grandson is two years older he is 7.
Thus,
The age of the granddaughter is 5
The age of the grandson is 7