The cell DOING the referencing isn't formatted properly.
CTRL+1 will open the format box.
You need to be careful with references, your problem shows how data can
LOOK one way but actually be another. The cell you're referencing
appears to have a long calculated value in it with many decimal places.
It is formatted to only show 1 decimal place...which is usually OK.
But if you start doing calculations against that cell, you'll start to
notice discrepancies in the resulting math. That's because the number is
really much longer than you're seeing.
To eliminate the discrepancy, you need to round off those values
properly. Look at the help files on ROUND and MROUND. You can do the
rounding in the cell itself or in the cells that reference that cell,
just remember to do it.