Children who struggle in mathematics have a limited understanding of the foundational processes of mathematics. A lack of conceptual understanding causes students to fall behind as they progress through the core curriculum. Children at high risk for developing mathematics disabilities fail to gain numeracy knowledge. The purpose of this case study was to investigate the effects of an explicit mathematics intervention using concrete-representational-abstract sequence to teach students to count in flexible ways and use skip counting as a strategy for multiplication for students with mathematics difficulties. Students were able to learn skip counting and improved in their multiplication abilities. Implications are also discussed.