The world has 7,5 billion people. How many of them are too fat and how many are starving?
Divide the right amount of people between the three categories.
(one person = 1 billion people)
When you click on 'check' you will see which pieces were correct and which ones were wrong.
Then you can click on retry and do it again.
(The reason I'm not going to use this is that it gives the wrong impression...)