This is fairly open ended, so I understand if people consider this to be off-topic.
I'm interested in creating math lessons where two groups each learn how to use a different simple math skill, and then the groups are combined and challenged with problem types that require both skills.
Here's a simple example:
Group A would learn the definition of factorial and run some easy factorial problems.
Group B would learn that if you have certain fractions (like $\frac{8 \cdot 15}{5}$) it's easier to cancel first and then multiply.
Combined Groups form with a mix of people from both groups A and B. They are given problems like evaluating $\frac{10!}{8!}$ where having both skills makes running the problem pretty easy.
Is there a specific name for this sort of collaborative learning? What are some fun/interesting problems to run in this way?