Scalable parallelism is when several computers work together to do different tasks at the same time to get something done faster. Imagine you're baking a giant cake—it would take you a really long time to bake it, but if you had a lot of friends over to help, you could break up the work into pieces and each friend could help with one part. That way, the cake would be ready much sooner than if you'd done it alone. Scalable parallelism is a bit like that, but instead of friends, it's computers working together to finish tasks quickly.