The Asian Monetary Unit is like having a special group piggy bank where several countries in Asia put in their money. This allows them to work together so they can buy things, like toys, that they might not be able to buy on their own.
Each country has their own money, like Japan has yen and Korea has won, but they agree to work together and use the same measuring stick to make sure everyone has the same amount of value in their piggy banks. Think of it like measuring sticks for building blocks- we all want them to be the same size so we can build towers together. In the same way, countries in Asia want to make sure their money is worth the same so they can agree on how much things cost and buy things together.
Instead of each country having different money and measuring sticks, they agree to use one type of each so they can all play together and help each other out. This way, when they go to buy or sell toys, food, or other things, they can make sure everyone has the same amount of value and everyone is happy!