Infamous for their blog post
about the dangers and inevitable failure of Khan Academy, Mathalicious
provides standards-based math lessons through real-world topics that are relevant to a students' lives. Their contextual approach means to help students make sense of the math, and develop both conceptual understanding and procedural fluency.
From what I've seen of the sample Mathalicious lessons, they seem to ask real questions in open-ended ways that require students to make sense of problems and not just churn out a numerical answer. Another element that I appreciate as a teacher is that the lessons are easily adaptable into a current curriculum and unit plan that has already been implemented in the classroom.
In terms of payment, they recently just started an experiment where they ask teachers to "pay what they can" for the membership plan. They suggest $20/month, but if that's too much, you can pay as little as $5/month. For a for-profit company, I think that's a really nice gesture to teachers paying out of pocket for resources.
The lessons on their own do not seem pedagogically sound enough to solidify math concepts for students. There is no fluidity or thematic connections between any of the lessons, even if they are grouped under the same broad categories, like Geometry and Functions.
At this point, all of our curriculum projects are free to any educators who want to access the material. I wonder if teachers think differently about paid lesson plans/resources and free lesson plans and whether or not one is viewed more trustworthy than the other. I think Rock & Roll Forever, Understanding Fiscal Responsibility, and Young Arts are very high quality curriculums that are also free. Will teachers think that it's too good to be true? Or should free and open educational resources become the norm?