Mortensen Math Trainer Bob Hazen owns and operates SAI the Summer Algebra Institute for Kids which is a half-day weeklong program for students in grades 3-6. To date, approximately 4000 students have attended SAI. Color, shape, size, texture, music, manipulatives, and hands-on games are used to teach some very substantive algebra in ways that connect it with the arithmetic kids already know. Bob has 3rd graders doing algebra that some high school students are unable to do.
What makes the Summer Algebra Institute for Kids so powerful is that Bob has identified principles or grand ideas that connect all math across the grades and topics so that what students learn about algebra during their time at SAI also helps them with fractions, place value, trigonometry, measurement units, and so on.
Bob also runs Algebra for Breakfast an online version of the Summer Algebra Institute for Kids.