From the link Bonusmom posted:
http://www.chs.bismarckschools.org/uploads/resources/1476/08_comparativedata.pdf

A student score at or above the following scores on a 6+ Mathematics Survey with Goals test
suggests student readiness for:
230 Introduction to Algebra
235 Algebra
245 Geometry

The chart gave median scores for grades 2-11. I wonder if the 6+ designation is significant or not.