Mat

As per 115JB, certain additions and deductions need to be done to the profit as per profit and loss account in order to arive at profit as MAT. One of them being,

deduction of unabsorbed depeciation or carried forwatd losses, whichever is less.

Hence, if any of the figure is NIL, then no deduction has to be made.

In your case, Rs 80 lacs can be deducted to arrive at book profit under MAT