Breaking it down:

B2: =IF(A2,"",MAX($A$1:A1)&"."&IF(B1="",1,MID(B1,FIND( ".",B1)+1,15)+1))


=IF(A2,""

if A2 is blank (or zero), then B2 will be blank. Otherwise

MAX($A$1:A1)

returns the largest value in column A up to the previous row. This
assumes that your numbers in column A are in ascending order, which
seems likely given your example.

&"."

append a decimal point.

&IF(B1="",1

If the cell above is blank (because the column A cell holds a value),
then append 1 to start the sequence, otherwise

MID(B1,FIND(".",B1)+1, 15)+1

Find the value to the right of the decimal point in the previous cell,
add 1, and append it to the "x."



In article . com,
"FireGeek822" wrote:

Thanks for the help. Not sure what is going on in your formula and
would like to understand it if you could explain. Typically, I like to
understand what I am building vs. just using someone's code.

Tammy