No. You usually hold a 7" tablet closer to your eyes than a 10" one. So, for its pixels to appear the same to your poor eyes as pixels on an 246 ppi iPad 3, it must have a pixel density of 290 or so.
You don't have to hold it any closer. I assume that there would just be less on the screen. Better to optimize for reading comfort than packing as much as possible on to the screen.
I didn't downvote you, but I'm skeptical of the claim. They're both hand-held devices. I don't generally hold my Galaxy Nexus closer to my face than my iPad.
FYI: I downvoted you because telcodud was explicitly not making a claim that Nexus 7 is "retina," and in your retina-calculation math you completely overlooked the actual (and correct) answer to mycodebreaks' question:
> Nexus 7 [is] not "retina"
> Nexus 7 is closer to iPad 3 than iPad 2.
What you did end up saying is correct but unrelated to the post you were disagreeing with.
I absolutely don't mind a downvote; I was just confused because I thought I was horribly wrong... My point was that it's not closer to iPad 3, it's really between iPad 2 and iPad 3. Anyway, it's not important :)
I actually did the math in my head (Thales) and thought 290 might be just about right, but if you want to be more accurate, use http://bhtooefr.org/displaycalc.htm . The number at bottom-right is the distance "at which individual pixels will no longer be distinguishable", a.k.a Retina.