A billion is a big number that has only recently become popular. It was such a large number that many people have not had a billion dollars in the last century. During this century, people are becoming aware of this amount, but the extent to how large it is may still be difficult to understand. When you look at a million, there are one thousand thousands in one million. So, there are one thousand millions in a billion.
If you place a thousand marbles in a line and then place another line of marbles next to it and keep doing this until you have one thousand lines of marbles, you would have one million marbles. Then if you create this lines of marbles a thousand times, you would have a billion marbles.
