Okay, kiddo! So, you know how there are lots of countries in the world like our country and some have more money than others? The G20 is a group of 20 countries that get together to talk about important stuff like money, trade, and how to make the world better.
But not all countries in the G20 are the same. Some are called "developing nations," which means they are working hard to become rich and powerful like the other countries in the G20. These countries are working on things like improving their economies, health care, education, and protecting the environment.
The developing nations in the G20 are important because they represent a significant part of the world's population and they have a lot of potential to grow and help make the world a better place. The other countries in the G20 want to help out and work with them so they can all collaborate and make better decisions for everyone.
So, in short, the G20 developing nations are a special group of countries that are working hard to grow and become strong, and the other countries in the G20 want to support them and work together for a better world.