Khan Academy individualize students' Math learning in their online program. The whole curriculum is common core aligned.

claridad de explicación en videos Estudiante de pre-medicina lo usa para complementar las conferencias y para el estudio del MCAT Realmente no usa preguntas de práctica o tareas Principalmente lo usa cuando la conferencia principal es confusa

For one topic, Khan Academy videos state really clearly - they are very very good for the beginners. You don't need to worry that you fail to understand something.