Although it works fine i now wish to be able to drag down the cell so i
get
=IF(G4-J4<0,G4-J4,G4-J4)+INDIRECT("'"&PrevSheet()&"'!H4")
=IF(G5-J5<0,G5-J5,G5-J5)+INDIRECT("'"&PrevSheet()&"'!H5")
=IF(G6-J6<0,G6-J6,G6-J6)+INDIRECT("'"&PrevSheet()&"'!H6") etc...

I IF part works. However the indirect bit stays at H4 eg..
=IF(G5-J5<0,G5-J5,G5-J5)+INDIRECT("'"&PrevSheet()&"'!H4")

I really dont want to have to manually go to each and change that
because i have hundreds of rows. Any suggestions?

Cheers in advance