This paper looks at the popularity of after-school mathematics by focusing on the Kumon and Russian School of Mathematics models. In 1954, Toru Kumon, a high school math teacher in Japan, designed a series of math worksheets to help improve the test scores of his son Takeshi, a second grader. Toru's goal was to teach Takeshi how to learn independently through the worksheets and improve his calculation skills prior to reaching high school. By working every day on the problems, Takeshi was able to reach the level of differential and integral calculus when he was just a few months into the sixth grade. The Kumon model is based on four elements: (1) Individualized instruction; (2) Self-learning; (3) Small-step worksheets; and (4) Kumon instructors. Parents who want to give their children a head start in math before elementary school can enroll them in Kumon as young as age 3. From that age they can stay with the program through high school or until they complete the program. In the U.S. alone, Kumon has grown from more than 182,000 students and nearly 1,300 centers in 2008 to more than 279,000 students and more than 1500 centers in 2018. While the Kumon method involves repeating mathematical processes until students over-learn them to automaticity, the Russian School of Mathematics (RSM) promotes itself as believing in just the opposite. The RSM model was founded by Inessa Rifkin in 1997 with Irina Khavinson, a friend, educator, and fellow Russian immigrant, after concluding that her son Ilya was not receiving the same mathematics education that she received as a student in the Soviet Union. Their goal was to translate their own experiences with specialized Russian math programs into a school that offered the same opportunity to American children. Two decades later about 25,000 students are enrolled with RSM today, in 40 locations in 11 states and Canada. Russian School of Mathematics students attend a classroom once per week for varying lengths of time, depending on grade: 90 minutes for kindergarten through third grade; two hours for grades four through six; and two-and-a-half hours for grades seven and above. Algebra and geometry are on separate tracks starting in the sixth grade, though students may enroll in both. This paper reviews each model's methods, highlights their best practices, and shows how they complement or run parallel with mathematics taught in traditional classrooms.