Earth+and+Space+History

=// 4,600,000,000 //=

I s that a BIG number?

It's so big, that we prefer to shorten it to

= 4.6 billion. =

If I were to tell you that something was **4.6 billion** years old, what questions would you have?

Investigation 1 Resource 1 History Channel: How the Earth Was Made; Birth of the Earth media type="custom" key="24631748"