Requesting 30 decimal places is wasted effort. As documented, Excel will
display no more than 15 significant figures. If you ask for more, Excel pads
them with zeros regardless of the actual values.

On the other hand, it takes 17 significant figures to uniquely identify the
binary representation of an IEEE double precision number (used by Excel and
almost all other software). Therefore, to determine what is going on, you
either need to use subtraction, such as
=(MOD(A1*10,10)+1-9)
(note the outer parentheses that prevent Excel from being overly "helpful"
and returning zero when Bernard's formula isn't really 9), or you can use
functions such as those at
http://groups.google.com/group/micro...06871cf92f8465

Jerry

"Roger Govier" wrote:

Hi Bernard

Yes, I get the same result as you with XL2003.
With the series 2.0,2.1 etc through to 3.0 in A1:A11 I get the letter
series
z,a,b,b,c,e,f,g,g,i,z
whereas with your second formula I get the correct series
z,a,b,c,d,e,f,g,h,i,z

Looking at the =MOD(A1,1)*10+1 part of the formula and the
=MOD(A1*10,10)+1without the Choose function the return is the series of
numbers 1,2,3,4,5,6,7,8,9,10,1 in both cases, with no detectable
difference even when extending decimal places to 30.

It therefore appears as though Choose is giving rise to the error.

Amending the first formula to
=CHOOSE(ROUND(MOD(A1,1)*10+1,0),"z","a","b","c","d ","e","f","g","h","i")
gives the correct results.
As you say, very odd indeed.

I would also like to send best wishes to you (and everyone else) for the
New Year.


--
Regards

Roger Govier


"Bernard Liengme" wrote in message
...
To help answer a question on this group, I wanted to convert the
decimal part of a number (in the set 1, 1.1, 1.2, ...... 9.7, 9.8,
9.9 ) to a letter. Thus 2.1 would yield a, 2.2 would give b.

I experimented with
=CHOOSE(MOD(A1,1)*10+1,"z","a","b","c","d","e","f" ,"g","h","i")
but it did not quite work (for example 3.8 gave 'g' and not 'h')
So I tried
=CHOOSE(MOD(A1*10,10)+1,"z","a","b","c","d","e","f ","g","h","i")
and this worked.

Odd since, at the integer level, =MOD(A1,1)*10+1 and =MOD(A1*10,10)+1
give the same result.

Using the Evaluate Formula tool (I work with XL 2003) I was unable to
see why my original formula did not work.
=CHOOSE(MOD(3.8,1)*10+1,"z","a","b","c","d","e","f ","g","h","i")
yields
=CHOOSE(9,"z","a","b","c","d","e","f","g","h","i") but the next result
is g not h
Very odd!!!
Happy New Year to all
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email