Tax is the amount of money you pay to the government depending on your salary and the cost of things you buy. But we have to admit this Rob, taxes are not popular. Rob: That's true. Many people don't like paying tax because they don't receive an immediate benefit from it. Some very rich people try to pay as little as possible. But one billionaire who thinks it's important to pay and create conditions for governments to fight poverty is Bill Gates. The founder of Microsoft earned a lot of money, retired and, with his wife Melinda, created a foundation to help the poor. The BBC asked him what the very rich have to do to help reduce poverty. Let's listen to his answer. What does he say rich people have to be? The word is an adjective. Bill Gates (philanthropist): Well, their obligation of course is to pay their taxes, but our advice to them is that they all look at taking their wealth and being philanthropic - both in their own country and to help the global poorest. That's a full-time work Melinda and I do, we find it very fulfilling, we love seeing the progress.