Lo (que es) fácil

[laepelba]

Sigh....

There are some things that are so difficult for me to understand, and I would bet that they are easy ... yet they escape me......

About a month ago, we had the following discussion about the sentence "see how easy this is": http://forums.tomisimo.org/showthread.php?t=9876 - I'm specifically looking at the discussion about #10 and the use of "lo fácil". I didn't really understand it then, but dropped it, hoping to understand it some day.

Now I'm doing another exercise in my workbook. The chapter/section is about relative pronouns, specifically the use of "lo que" and "lo cual". They have the following sentence and translation:
English: Students want what is easy.
Translation: Los estudiantes quieren lo fácil.

I thought it should have been "lo que es fácil". (Especially given that every single other sentence in the three sets of exercises in this section use "lo que" or "lo cual".)

Is "lo que es fácil" acceptable? Or does it sound strange?

I'm still stuck on this concept...........