GMAT Math

Just completed the Quant section of the practice test from the OG 11th edition and only got 26 correct out of 48, which is miserable. I found it to be difficult as compared to the questions in the Quant review book, has anyone else felt the same or does it mean I have to really work hard to achieve a score of 700+

The Diagnostic in OG is scaled to be much harder than the actual GMAT. You shouldn't worry too much (its also not supposed to be timed)

my feeling is that the OG11-review (green book) is easier than the OG11 (yellow book).

yeah...the diagnostic test is definitely harder than most of the rest of the book. a couple of those questions are as hard as anything else in OG or GMATPrep.