Nuanced aptitude distinction from common-core education

Recent NYT has an article about the impact of standard common-core education in NY state. The test score in 2013 (after common-core) is 58% worse than in 2012 (before common-core). The common-core guidelines seem to be just the basic training and it proves that US students have lagged behind way too long. By adopting the rigorous common-core, according to NYT, only the strong dedication from teachers can make a difference. Typical 4th grade math question under common core is as follows: "A club’s first meeting was attended by 28 people. The first meeting was attended by 4 times as many people as the second meeting. How many people attended the second meeting?" The question should be pretty easy but it stumps many 4th-grade students in NY city.
http://www.nytimes.com/2014/06/15/education/common-core-in-9-year-old-eyes.html?_r=0