Kumon Education and Research Association of Japan is a corporation and an education brand created by Toru Kumon. The Kumon method is the math and reading educational method which is practiced in the Kumon centers. Kumon is a math and reading program intended to supplement rather than replace school lessons. Students do not work together as a class, but progress through the program at their own pace, moving on to the next level when they have achieved mastery of the previous level. Students are guided by trained Kumon Instructors and Assistants. Mastery is defined as speed (using a standard completion time) and accuracy.[3] They take an achievement test at the end of each level.