The indexed pool total is checked without collapsing source identity. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Three index labels keep three sources separate
The index labels are A,B,C. Each row carries 8 unique reads.
A:8,B:8,C:8
The pool total is twenty-four unique reads
The total unique-read count is 24, but the index rows remain visible.