Well, we haven't experience exactly the same acceleration, but we did consider it last year. DS (rising 5th grader) accelerated from 2nd grade to 4th grade math in 2nd grade, then skipped 6th grade math to study pre-algebra in 4th grade. We decided against accelerating to algebra in 4th grade for a variety of reasons and we have been happy with our choice. However, I believe that had we chosen to skip both 6th grade math and pre-algebra, that would have been fine also.
I am not familiar with ERB so do not know how comprehensive or reliable the pre-algebra portion of the test is as opposed to accepted national algebra readiness measures like the one out of IOWA. In any event, DS had a 100% mastery by the measure provided by ALEKS before 4th grade and a top score on a national algebra readiness test at the end of 4th grade. He gained both a broader and a deepter mathematical knowledge from the year in pre-algebra. Furthermore, he covered lots of materials which are absent from these algebra readiness tests.
I am not sure if the same holds true across the country, but pre-algebra is really a misnomer in our district and we are on the way to changing the name across the board. In essence, pre-algebra is the "PASSPORT" to algebra and geometry. In the case of DS' gifted pre-algebra textbook, the breakdown was probably 60%/40% (pre-algebra/pre-geometry & pre-trigonometry). Learning the six trigonmetric functions and using it to solve real world application problems were one of the highlights of the pre-algebra course for DS.
If you believe that your DS has negligible gaps, then I would advocate convincing the school to put him in the one-year algebra course so he won't be stuck with the mediocre/slow students. If that option is not possible, I would recommend taking pre-algebra this year with the advanced students and then covering algebra in a single year with the advanced students. In addition to what I have shared above, it has been my experience that the GT classes working one year above have always been substantially more vigorous that the at level classes one year ahead (4th grade GT math doing 5th grade curriculum is more vigorous than 5th grade regular class doing 5th grade curriculum). I believe that is the reason why in our district acceleration is only allowed if the student qualifies for the GT class the year above.
Last edited by Quantum2003; 08/08/13 11:34 AM. Reason: another attempt to correct [SPAM] back to "pass-port"