hi, shaqil !

"Gary''s Student" wrote:
Format Cells... Number Custom:
0\,00\,000.00

Sorry, but when i write 100 it shows 0,00,100.00 that looks odd.
when a figure should be less that 100,000.00 then it should look as usual...

you can "hide" leading commas if you "play" with custom formats (i.e.)

[=100000]#\,##\,##0.00;#,##0.00

[9999999]##\,##\,##\,##0;[99999]##\,##\,##0;#,##0

for negative numbers try with the following custom number format:
[<-9999999]-##\,##\,##\,##0;[<-99999]-##\,##\,##0;#,##0

(however) you won't be able to mix positive/negative number using only one format
so, you might want to give a try an extra cell/column and ws-functions
(i.e.) assuming the number in 'A1':

=text(a1,rept("##\,",match(len(abs(a1)),{3;4;6;8})-1)&"##0")

hth,
hector.