Danish Numbers 20–100

This is where Danish numbers get famously unusual. While 20 and 30 are relatively normal, 40–90 come from an old vigesimal (base-20) counting system — similar to how French uses "quatre-vingts" (4 × 20) for 80.

Danish

English

Origin

tyve

twenty

Straightforward — related to Old Norse

tredive

thirty

Straightforward — related to Old Norse

fyrre

forty

Short for "fyrretyve" — 2 × 20

halvtreds

fifty

Half-way to the 3rd score — 2½ × 20

tres

sixty

3 × 20 (three score)

halvfjerds

seventy

Half-way to the 4th score — 3½ × 20

firs

eighty

4 × 20 (four score)

halvfems

ninety

Half-way to the 5th score — 4½ × 20

The Base-20 System

A "score" is 20. The Danish tens from 50 onward are built by counting scores and half-scores:

halvtreds (50)

halvtredje [sindestyve] = half-way to the 3rd score → 2½ × 20 = 50

tres (60)

tre[sindestyve] = 3 × 20 = 60

halvfjerds (70)

halvfjerde [sindestyve] = half-way to the 4th score → 3½ × 20 = 70

firs (80)

fir[sindestyve] = 4 × 20 = 80

halvfems (90)

halvfemte [sindestyve] = half-way to the 5th score → 4½ × 20 = 90

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Learning tip

Don't worry about the etymology too much — most Danes don't think about scores when they say these words. Just learn them as vocabulary: halvtreds, tres, halvfjerds, firs, halvfems. The pattern (halv-X-s alternating with X-s) can help you remember the order.