The topic of this article is about the words "Тоже" [tozhi] (also) and "Также" [takzhi] (as well), their grammatical difference and correct usage. The difference in the usage depends on what part of speech they are presented.
Well, the conjunctions "Тоже" and "Также" are synonyms, they have similar meaning which is closed to the conjunction "И" [i] (and) i.e. they mean the adding of something to something. In some cases we can use the conjunctions "Также" and "Тоже" instead of "И". Sometimes they are interchangeable but sometimes there is a difference between them. The point is that we should understand which word has the meaning of joining and cognation. Here is a simple example:
Моя мама математик. Я тоже интересуюсь математикой - My mom is a methematician. I'm also interested in mathematics.
(I'm also = I am like my mom).
Мне нравится физика. Я также интересуюсь математикой - I like physics. I'm interested in mathematics as well.
(I'm interested in mathematics as well = I like as physics as mathematics).
Sometimes it's impossible to replace one conjunction with another. We can't use the word "тоже" in the following example.
В аудитории находились студенты, а также профессор - There were students in the classroom as well as a professor.
В аудитории находились студенты и профессор - There were students and a professor in the classroom.
We write the conjunctions "Тоже" and "Также" in one word. It's important not to mix them up with the combination of a pronoun with particle "То же" and adverb with particle "Так же" which are written separately as all distinctive parts of speech do.
То же место, тот же час - The same place, the same time.
It can be complicated because the word "Тоже" sometimes can be as a conjunction as a particle with its own meanings.
Here is the difference.
The adverb "Тоже" means "in the same way like other do".
Ты тоже говоришь по-русски (как и я) - You also speak Russian (as I do).
The particle "Тоже" expresses distrust, irony or sarcasm. It is often used in the phrase "тоже мне" [tozho mn'e]. For example:
Тоже мне музыкант! - And he calls himself a singer!