A dream about addition can be a sign that you are missing something in your life.
If you are adding something in a dream, it can mean that you think you can solve a problem or make your life better by adding something to your life.
This can be something material, such as money or property, or something more abstract, such as love or spiritual satisfaction.
The numbers that you are adding in your dream can be significant. Do they refer to an important date in your life, the number of people in your family or something else?
A dream that you are in school watching someone solve an addition problem can mean that you are hoping that someone will help you to obtain the solution to a problem that you have in waking life.