"Four score and seven years ago" from the Gettysburg Address... Many languages have or had words for counting in 20's. They've just mostly gone out of fashion.
vidarh
Wiktionary suggests the common proto-Germanic root of eleven/twelve, elf/zwölf are likely to have been "ainalif" and "twalif" - "one left over" and "two left over".
They're both Germanic languages, just like Dutch, German, Norwegian, Danish and a few others. Same origin. All of them have variations of tre/dre/drei/thir/þre/þrēo (say them with sounds halfway between t and d as the first sound, and you'll see how similar they are) followed by variations of ten/teen/tin/tan/ton/tien/zehn as a suffix for ten (again, pick a halfway point between t and z and it's easier to see how similar they are).
In Old English it was þrēotīene ( þ is "th"), and in Old Norse it was þrettán, same as modern Icelandic, so the first common root is even further back, but you can see the similarity. The *hypothesized proto-Germanic root is þritehun. (þriz + tehun.
But, it goes back even further than that. The Romance languages (tres, trois etc) shares the same proto-Indo-European root (hypothesized to be tréyes) for three with proto-Germanic.
The names for numbers are ancient, and though not always recognisable, sometimes recognizable variants pop up even further away than you'd expect. E.g. Pashto (Southeastern Iran) has dre for three, Sanskrit has trí, Indonesian has tri, all of them descendants of the same proto-Indo-European root.
Sadly, while you can export everything, you can't import posts in Mastodon without having direct access to the database and poking about.
You can import following lists, bookmarks, blocks and mutes, though.