Imagine you're playing a game with your friends and some people want to play the game one way, and others want to play it another way. What do you do?
Some people might say, "We should do it my way!" and get really loud and upset when others don't agree. Other people might say, "Let's just do it half my way and half your way!" and try to find a compromise. This is what centrism is all about: trying to find a balance between different ideas so everyone can be happier.
In the United Kingdom, there are lots of different political ideas and parties. Some people want the government to do more things to help people, like providing free health care or education. Other people think the government should do less and let people make their own choices.
Centrist politicians in the UK might say, "Let's find a way to do both. We can provide free health care and education, but also let people make their own choices in other areas." They try to find a balance so people on both sides of an issue can be happy or at least not too unhappy.
Some people like centrism because it means they don't have to choose one side or the other. They can take bits from both sides and make their own opinions. Other people don't like centrism because they feel like it's wishy-washy or doesn't have strong principles.
Overall, centrism is a way of trying to find common ground between different ideas so everyone can be happier. In the United Kingdom, centrism is a popular approach to politics that many people believe can help solve problems and keep the country moving forward.