Holding forward work fixed while the return path changes makes net cycle work a checked difference. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A small return path leaves thirty joules net
Forward work is fixed at 36 joules. Returning only 6 joules leaves net work 30 joules.
36−6=30
The original audit row returns half
With the same forward work, return work 18 joules leaves net work 18 joules.
36−18=18
A large return path leaves only six joules
Returning 30 joules leaves just 6 joules net. Three rows show that hysteresis is the unreturned area.