I have two columns L3:M27636.
In column L3:L27636 I have numbers 1234, 4321 etc.
In column M3:M27636 I have either blank cells or numbers 709000.
If column L and M has a number they would match through the worksheet
for example if L4 has 1234 and M4 has 709000 then anywhere 1234 appears in
column L the corresponding cell in column M would be 709000.

I would like a formula that says if M3 is blank, look in L3:l27636, match
this to L3 and if there is a match and has data in the corresponding cell in
column M insert the number or else insert a blank.

I tried =IF(ISBLANK(M3),VLOOKUP(L3,$L$2:$M$27635,2,FALSE), M3) which didn't
work.