OmarAdnan

R2 shows the total variation in the dependent variable explained by the independent variables..you want this to be high for a good model. Problem is, R2 will always increase when you add more independent variables, even if they aren't contributing to the model.
Therefore R2 adjusted takes this into account and gives you a more realistic total variation explained. It's always equal to or less than R2..and can actually even be negative in special circumstances.

Hope this helped !