This collection from NRICH provides activities to help learners think and work like a mathematician. Tasks have students exploring, questioning, working systematically, visualizing, conjecturing, explaining, generalizing and justifying. Activities are organized under specific strategies and processes.

This article offers advice to educators on developing learners' collaboration skills through problem solving. The author presents six categories of tasks, each of which addresses a set of teamwork skills (e.g. listening, sharing, reflecting) and includes several tasks which could serve as the vehicle. Links to the tasks, printable materials, and other resources are included.

This is a lesson plan for third grade students. Students will choose one math skill or concept they learned this year and come up with a real world example of that concept. For example, finding the perimeter of their yard for a fence. They will create a three scene storyboard and then act out their storyboard. With the help of the teacher, they will film this example and later share it with the class. Students will peer review each others videos and participate in a discussion about the topic.  

These 10 strategy games from around the world develop spatial skills and strategic thinking. Two of them include interactive versions, but all can be played with simple materials indoors or out.

This webpage for parents and caregivers describes the various types of resources available at NRICH, a project at the University of Cambrige: rich problems, strategy games, posters, and articles on mathematically gifted children. There are links to these resources and more.

This assignment is great for the days the students need something to do at home on a digital learning day!