A computer system that has two or more processing engines (PE), each capable of performing one or more operations on one or more operands but one or more of the PEs performs the operations unreliably. Initial results of each operation are debiased to create a debiased result used by the system instead of the initial result. The debiased result has an expected value equal to a correct output where the correct output is the initial result the respective operation would have produced if the respective operation performed was reliable.