What decimal is equivalent to 7/8?

Once again, John McCann is correct. 

How can you do this yourself?  Remember that a fraction is another way to express division.  7/8 is the same as 7 divided by 8, or 0.875

1/2 is 1 divided by 2, or 0.5

1/4 is 1 divided by 4, or 0.25