Visible charge is scanned across finite source and response ledgers. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Visible charge is signed source plus response
This is a finite signed shielding ledger. It does not claim a real exponential charge profile.
8C+(−3C)=5C
A stronger opposite response hides more source charge
The visible charge column is just signed addition. The zero row is complete finite cancellation, not field disappearance everywhere.