A chip readout should carry the controlled thermal work that preceded it. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Each ramp has a checked heat budget
Heat capacity 4 J/K times temperature change 15 K gives one ramp energy 60 J.
Q=CΔT=4J/K⋅15K=60J
The total ramp energy becomes a source value
Two equal ramps give total ramp energy 120 J. The ledger cites the checked thermo heat bar.