Question

Are there any corrections that need to be made to this paragraph:
En mi clase de algebra, no tengo muchas reglas. El profesor es muy simpatico y gracioso. En mi clase, hay que presentar atencion al profesor. Tambien, hay que levantar el mano a menudo. Se prohibe llegar tarde a la clase. Tambien se prohibe usar el telefono durante de la clase.

Answer 1

I'd change "no tengo muchas reglas" in the first sentence,
to "no hay muchas reglas."
(It means, "there aren't many rules.")

I'd change "hay que presentar atencion" in the third sentence,
to "hay que prestar atencion."
(It means something along the lines of "we have to pay attention.")

I'd change "el mano" in the fourth sentence,
to "la mano."
("Mano" is actually a feminine noun. It's a bit irregular, in that way.)

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Aside from those three little things, it sounds good!

Answer 2

As usual, InYourHead is right on. I'd also remove the last "de" in the last sentence so that it reads: "durante la clase".

Answer 3

The sentences sound a bit awkward (you begin 2 of them with "en mi clase" and 2 with "Tambien") but otherwise @InYourHead and @Peachy947 pointed out the things to correct.
Its also important that you use tildes (´) even if you are typing (álgebra, simpático, atención, También, prohíbe, teléfono)