"Ich denke auch" ----> it has the meaning that you agree with somebody..... for example Mr.X says: I think it will be rain soon.... Than says Mr. Y: "Das denke ich auch" (I also think so) .... So he agrees with Mr.X statement :) 2. ich denke schon. ----> It does have actually almost the same meaning like " Ich denke auch" but it depends on the sentences when you use this phrase or the other :) "Ich denke schon" is more related to question .... but you express with this phrase that you agree with somebody ..... for example: Do you think that Mr.X will arrive tomorrow in Berlin ? than can you reply this question if you want say yes you think so ... ("Ich denke schon") but you shouldn´t use this phrase in business activities etc. because it´s actually colloquial :) 3. Question : "I think so" in German : " Ich glaube ja" or " Ich denke schon" and a additional advice, you wrote in the topic: "Was ist der Unterschied zwieschen diese Sätze?" the better phrase would be: " Was ist der Unterschied zwischen diesen Sätzen?" ...... diesen und Sätzen because it´s plural ..... and zwischen without that "e" in the center :D I hope I could help you a bit best regards Daniel

Ich bin der gleichen Meinung.

auch = too A. Der Kaffee ist gut. B. Denke ich auch. A. Ist der Kaffee gut? B. Ich denke schon.