A perpendicular field-area ledger gives magnetic flux. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Perpendicular field times area sets flux
A field of 3 tesla through area 2 square meters gives flux 6 webers.
Φ=3×2=6Wb
This is only the perpendicular training case
The clean area ledger is 3 times 2, with no angle factor.