Sometimes R has a misleading way of displaying values.  Check out this series of commands:

At first I thought that R was automatically rounding the numbers.  So the value got changed if it exceeded certain number of digits.  But in reality R know the real value; it just chooses to display it differently.  To prove this I executed this series of commands:

Notice that the value of ‘a’ is not 1111112 but 11111111.5.  I kept on looking and found out that you can modify the way R displays the numbers.  You just need to modify the global variable digits.  This will modify the way numbers are displayed for the rest of the R session.

options(digits=15)

But notice that even though you change the digits option, you don’t change the values themselves.