All of the Official Guides (OG 12, OG 11, Verbal Review, Quant Review) have questions arrange in order of ascending difficulty.

I hesitate to use terms like "easy," however. Please remember that difficulty on the GMAT is based on the percentage of people that get a question right. If more people get a question right it is considered to be of lower difficulty. Now this same question may not appear to be "easier" to an particular person.

You or I might look at it and think it is pretty tough, but if more people get it it right it will be earlier in the book. Another question might simply ask if "x is even" and we might think it is simple, but it fools people and most get it wrong so this one will be near the end of the section.

And do keep in mind that these are retired GMAT questions so they have lots of data as to the relative percent of people who get these questions right/ wrong.

It is very interesting to see what questions are considered to be easier/ harder....