Imagine that you are a little kid and you have to decide on what game to play with your friends. You want everyone to be happy and have fun, so you try to pick a game that makes everyone happy.
Act utilitarianism is a way of making decisions where you think about what would make the most people happy in a specific situation. You try to choose the thing that will make the most people happy, even if it doesn't make you happy.
For example, let's say you have a candy bar and your two friends also want it. You know you could keep the candy bar and have it for yourself, but you also know that it would make your friends happy if they got a piece. So, you decide to divide the candy bar into three equal pieces and share it with your friends. This shows act utilitarianism because you made the decision that would make the most people happy, even if it means you don’t get as much candy for yourself.
Overall, act utilitarianism is all about making decisions that will make the most people happy, even if it doesn’t benefit you personally. It’s like being a really good friend and always trying to make others happy.