At a fixed checked gradient, distance changes the predicted signal level. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
One metre adds two signal units
The source gradient is 2 per metre. One metre from starting signal 6 predicts signal 8.
6+2⋅1=8
Two metres predicts ten
Distance 2 m adds 4 signal units, so predicted signal is 10.
6+2⋅2=10
Three metres predicts twelve
Distance 3 m predicts signal 12. No sensor noise or adaptation is claimed.