A toy phonon packet ledger cites the accepted mode. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Wave speed and wavelength give the mode frequency
Speed 16 meters per second over wavelength 8 meters gives frequency 2 hertz.
f=v/λ=16/8=2Hz
Phonon packet energy is counted in the training model
Four packets with h equal to 3 joules per hertz and frequency 2 hertz carry 24 joules.