Just to correct this map (don't worry it's still super complicated), what we really say is this:
**2 and half-fifth times 20** ("tooghalvfemsindstyve", a slightly (messed) up "tooghalvfemtesindetyve")
\- where half-fifth ("halvfemte") is an outdated way of saying 4.5 (halfway from 4 to 5).
However, that's the long form, we've shortened the word in speech and writing to "tooghalvfems", which, on the face of it, translated without context, is "twoandhalffives".