Facts:

Solel Boneh (Nigeria) Ltd appellant\defendant is the main contractor to the University of Port Harcourt Teaching Hospital Project. They employed the services of Canitec International Company Ltd as sub-contractor to execute the laying of terrazzo works and skirting works in “Block J” at the University of Port Harcourt. The said subcontract was settled at the rates of N1,400.00 (One thousand four hundred Naira) per square metre and N300.00 (three hundred Naira) per linear metre respectively: The terms of the subcontract were documented and executed as the subcontract Agreement and sited as “Exhit A”. The job was successfully executed and dully paid for in terms of “Exhibit A”. The Appellant subsequently made another offer to the Respondent termed “an extension of the existing subcontract to cover the “Mortuary Block and Block H,” at the same rate with the earlier one which had been executed and concluded, this letter of extension is marked as “Exhibit B