Having knowledge about diffrent generations help teacher to undrstand differeces  between older grnerations and young generations.For example old generation have alot of chalenges about technology .They do not know how to make powerpoin ,On the other hand younger generations, they start working with computer and social media from early age, younger generation they are faster , they search everything and they use internet and computer easily. knowing about weakness and strengh of each group help teacher to have a right sterategy for teaching effectively.