A residual budget is scanned below, at, and above the acceptance limit. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Zero residual budget passes the gate
All five readings match the target, so the squared budget is zero.
0≤9⇒1
Equality at the limit still passes
One reading at three volts gives budget nine, exactly at the limit.
9≤9⇒1
One extra residual square rejects the row
Adding a one-volt residual raises the budget to ten, so the row fails.