How I Use It
Students in my classroom use Scratch as one of their math extension activities. They are required to have a certain number of components (Sprites, actions, etc) but the learning is otherwise open in such a way that they can really let their creativity shine! It has an adequate amount of support (for further support, I also direct students to Code.org's Code Studio lessons) for most students in grades 4-6 and students who really grasp the concept can use Scratch to create quite impressive digital projects--games, interactive stories--the sky is the limit!
Scratch encourages my students to use broader math ideas (attending to precision, creating a process to solve a problem, understanding repeated reasoning and structure, etc.) It also supports growth in 21st century skills--especially system's thinking, problem solving and resiliency. They are forced to really think about the details and how those impact the whole. I also encourage students to work together with Scratch, which also taps into the ability to collaborate and communicate effectively to solve a problem.
Coding isn't just for fun, or for an hour once a year (though the Hour of Code is a GREAT place to start). It truly reaches higher level thinking skills that transfer across content. As it is highly engaging and open enough to support students along a continuum of understanding, it can be great for personalization and differentiation. My only suggestion might be to have more "on demand" videos (examples or tutorials) that students could click when they get stuck instead of full tutorials and a menu of help videos that students have to search for. Students have to demonstrate flexibility and resiliency as they use Scratch, and these skills ultimately make them better learners no matter what they are learning. They become better risk takers and problem solvers, which has translated into growth and higher achievement.