A fixed shift and threshold expose base index as a checked readout source. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Base row 1 gives readout bit 0
Base index 6 plus fixed shift 1 gives observed index 7 against threshold 9.
6+1=7,b=0
Base row 2 gives readout bit 1
Base index 8 plus fixed shift 1 gives observed index 9 against threshold 9.
8+1=9,b=1
Base row 3 gives readout bit 1
Base index 10 plus fixed shift 1 gives observed index 11 against threshold 9.
10+1=11,b=1
Base index can move the same shifted readout across threshold
The shift and threshold stay fixed. The base source decides whether the observed index lands below, at, or above the threshold.