Thanks Mike, I guessed it may be down to a rounding error

Cheers
Chris

"Mike H" wrote:

Chris,

It's all to do with the way Excel does arithmetic. If you do you sum 1.7-1.6
and expand the formula cell to 9 decimal places you'll see the answer comes
out as 0.0999999 and while that may seem odd it entirely meets the IEEE
standard for floating point arithmetic.

Have a look here for a full explanation

http://support.microsoft.com/default.aspx/kb/78113

Now to your proble, try this

=IF(ROUND(C1,1)=0.1,"yes","no")

Mike



"Chris B" wrote:

Hi,

I have set up the following If function to determine if the answer to a
simple subtraction of two decimal numbers is 0.1.

=IF(C1=0.1,"yes","no")

The calculation is merely C1=A1-B1

However, for some calculations it is giving the answer "no" when the answer
is clearly 0.1!

1.7-1.6 gives a no response as does 1.4-1.3. Interestingly, from 4.1-4 all
answers are no!

Hope someone can help
Cheers