A mode label must cite the checked LC source. 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 platform mode cites one LC source
The mode label is accepted only because the same source carries 1 henry, 1 farad, and frequency square 1.
L=1H,C=1F,ω2=1s−2
This is a frequency-square training model
The book keeps the exact square 1 and does not compute a rounded oscillation frequency.