Common core standards are more robust than many that are currently in place. The math examples particularly "division is postponed from 5th to 6th grade" implies that it won't be taught in grade five which is false. It means that students won't be required to have mastered the concept until grade 6. Part of the reason our students fare so poorly on math is that not enough time is spent in the lower grades for students to have a firm grasp of number sense. We have moved from mastery of concepts to exposure to a wider variety of math concepts. We allow the use of calculators before kids have enough number sense to recognize "a good estimate." As a parent and teacher I feel that the Common Core standards are robust and a great place to start.