One way:

select B2:Bx. Choose Format/Conditional Formatting...

CF1: Formula is =(B2-B1)1
Format1: <pattern/<some color

or, without sorting, select column B (with B1 active):

CF1: Formula is =AND(B1MIN(B:B),COUNTIF(B:B,B1-1)=0)

Both CF's will activate if there are missing numbers before them.


In article ,
DTTODGG wrote:

Hello, I'm looking for a way to quickly find what numbers are missing in
column B. I can sort them ascending, but how do I find if there are missing
numbers?