cant get this Grade 10 Science Right!!!

Before any one says anything, i am graed 10 (im not a adult). I have missed the last week of school and all the lessons and then my teacher droped a sheet off at my house for me to do (and im not to sure abotu how to do it). Considering our school system sucks and in grade 9 we did nothing im kind of stuck. Can some one help me (and please dont make fun of how basic it is, every one has to start the science off some where)

Q. Write a Double Displacment Reaction for Aluminum Sulfate and Calcium Hydroixide.
A. Al2(SO4)3 + CaOH2 --> AlOH3 + Ca(SO4)2

Thats all i could come up with from pretty much guessing, the thing is though that its not balanced, can some one help me out?

Thanks.

Calcium sulfate is Ca SO4 not Ca (SO4)2.

So, it would be:

Al2(SO4)3 + 3[Ca(OH)2] --> 2[Al(OH)3] + 3[Ca(SO4)]

Hope that helps.
I used to make such mistakes too.