Translation of invaluable in Spanish

There is a small misunderstanding about the homework. I can do them, but they will be too confusing? I am trying to find the article from where I took the sentences in order to ease the task for all students.
I'm quite tired too by now. So, if it doesn't work just drop me an email and I'll see it first thing in the morning. I wanted to add new words to the dictionary however the other issues kept me more busy than I have imagined.
It's very good for me to be a member at Vocabulix be because I meet many new people. I'm currently being trained to be travel consultant and I really need English and Spanish and maybe other languages.