Abstract: This paper examines the cognitive and curricular problems of Common Core elementary mathematics. Through analysis of Big Ideas Math and related instructional practices, it argues that, visual representations are employed excessively and without sufficient transition to symbolic reasoning and mathematical abstraction. At the same time, standard algorithms and procedural memory are de-emphasized, while multiple strategies are treated as goals in themselves rather than as means to efficient problem solving.The paper further argues that the opposition between understanding and memorization reflects a serious cognitive misconception. In practice, the proliferation of visual models and solution methods tends to keep instruction at the level of surface features rather than guiding students toward deeper conceptual structure. As a result, the curriculum becomes diffuse and overloaded, increasing students’ burden and extending learning time. Difficulties in fractions among American students reflect these deeper structural and cognitive problems.The study concludes that elementary mathematics should remain grounded in practicality, clarity, and coherent procedural structure so that most students can achieve solid mastery.