Subtract Previous Cell's Value from LOOKUP Result

[dauerad]

Hello,

I have several rows with dates several dates in each column marking milestones of a task. Using LOOKUP, I have identified the last cell with a date within it and displayed the date using the following formula:

=LOOKUP(2,1 / (ISNUMBER(A1:G1)),A1:G1)

Is there a formula I can use to subtract the above result from the cell immediately preceding it?

Sincerely,

Anthony

 

[Jonmo1]

Try

=LOOKUP(2,1 / (ISNUMBER(A1:F1)),A1:F1)-LOOKUP(2,1 / (ISNUMBER(A1:G1)),A1:G1)

 

[snjpverma]

Try

=LOOKUP(2,1/(ISNUMBER(A1:G1)),A1:G1)-INDEX(A1:G1,MATCH(9.99E+307,A1:G1)-1)