I have a 1 year lease for student housing which I am trying to vacate. I have found a discrepancy on the lease: On the first page, there is an amortization column with a total at the bottom for the 12 month lease. On the second page, there is a blank for writing in the total amount for 12 months. The amount which is written in this blank is actually the monthly amount not the grand total. Could this discrepancy be used as a basis of invalidating the lease?

Not even close. An obvious typo is not going to void the contract. Especially if you signed it with the mistake.