This seems to do what you want:

Enter this formula in D1 as an array using the key combination of
CTRL,SHIFT,ENTER (not just ENTER):

=IF(ISERROR(SMALL(IF(ISNUMBER(MATCH(A$1:A$4+3,B$1: B$4,0)),ROW(A$1:A$4)-MIN(ROW(A$1:A$4))+1),ROWS($1:1))),"",INDEX(A$1:A$4 ,SMALL(IF(ISNUMBER(MATCH(A$1:A$4+3,B$1:B$4,0)),ROW (A$1:A$4)-MIN(ROW(A$1:A$4))+1),ROWS($1:1))))

Enter this formula in E1:

=IF(D1="","",D1+3)

Select both D1 and E1 and copy down until you get blanks.

Biff

"Jason" wrote in message
...
Hi,

I have two column of number, A and B. I would like to find all the
possibility for (# in B)- (#in A) is equal to 3 then return the
corresponding
numbers.

e.g

A B
1 3
2 4
5 8
7 13

4-1=3, return 1 & 4
8-5=5, return 5 & 8

Any input would be helpful
Jason