Ok kiddo, so you know how some people believe in one God, right? Well, ethical monotheism is a type of belief where they think that this one God wants us to be good people and do good things.
Imagine you have a really nice toy car, and your mommy tells you to share it with your friends because it will make them happy. That's just like how God wants us to share our toys, be kind to others, and be honest. He wants us to do things that make people happy and not hurt others.
Ethical monotheism is also about loving and respecting God, and following his guidelines on how to treat ourselves and others. It teaches us to be fair and truthful, and to help people in need.
So, in short, ethical monotheism is a belief that there is one God who wants us to be good and treat others with kindness and respect.