What is interdependence? At its most basic, it's a relationship in which members depend on each other for something. If certain foods grow in one region, and ores are produced in another, this sets up conditions for people in the first region to become skilled farmers and the people in the second to be skilled miners or metalworkers. If farmers want tools and metalworkers want food, their regions may become dependent on each other for wheat grown in the first region and plows manufactured in the second region. If so, they have entered into an interdependent relationship.

Designed for second grade classrooms, "What Makes Me Become We?", is a structured inquiry into economic interdependence that focuses on how people meet their wants and needs, and the challenges they face in this quest.

http://www.c3teachers.org/wp-content/uploads/2015/08/NewYork_2_Economic_Interdependence.pdf

The concept of barter can be used to prepare early-grades students to learn about economic interdependence. In this lesson plan from Scholastic, students will learn the benefits and drawbacks of barter by taking on the role of colonists in the New World who must trade for their daily necessities.  

https://www.mint.com/barter-system-history-the-past-and-present/

Barter is one aspect of trade. As trade and productivity increased and cultures began exchanging ideas, economic systems expanded, evolved, and became more integrated, resulting in a higher degree of interdependence.