It is incredibly important for students who are at-risk for mathematics failure or who have a disability which hinders mathematical performance to improve in their mathematical achievement. One way to improve mathematical achievement is through building fluency in mathematics. Fluency in mathematics is the ability to solve problems automatically and with accuracy. One method of building fluency for students who are at-risk or who have a disability includes the concrete-representational-abstract sequence of instruction that is paired with strategic instruction (CRA-SI). A brief overview is provided on CRA-SI instruction along with a review of the literature that shows CRA-SI instruction as effective instruction for students who are at-risk or who have a disability.