Computation of tax liability: aggregate incomes, apply deductions and rebates, add surcharge and cess, then adjust for prepaid taxes. Computation begins by aggregating head-wise incomes, applying set-off of losses and Chapter VI-A deductions to determine taxable income; tax is computed at applicable rates, reduced by rebates, increased by surcharge and 4% health and education cess, and then adjusted for statutory rebates and prepaid taxes to yield the final tax liability for the year. MAT and AMT provisions apply where relevant.