Is it reasonable for numerals to behave like verbs?

Question

I am aware that adjectives can pattern like verbs in some natural languages. Is it reasonable for numerals to do the same? Thus

Some balls four.
There are four balls.

Fouring the balls were orange.
The four balls were orange.

Of course, my conlang has more interesting verbal forms than we have in English. Is something like this attested in a natural language?

Answer 1

One clear-cut example of a language that treats many things like predicates, numerals included, is Khoekhoe.

Khoekhoe marks many kinds of predicates the same way, including numerals. The paper argues that all three of the open word classes (nouns, verbs, and adjectives) in Khoekhoe can be analyzed as primarily predicates and non-predicative usage requires more morphology, specifically person-number-gender (PNG) affixes. Nominalizing stuff with a PNG clitic is extremely productive in Khoekhoe.

Here is an excerpt from page 3 of 21 from Predication and NP Structure in an Omnipredicative Language: The Case of Khoekhoe by Michael Hahn.

Khoekhoe is an SOV language. The V slot may be occupied by a word from any of the three open word classes: a verb (1a), an adjective (1b), or a noun (1cd). Both commons nouns (1c) and proper nouns (1d) can be used. Even deictic elements (1e-f), numerals (1g), and possessives (1h) can act as predicates. While the choice of the TAM marker depends on the predicate, the syntactic behaviour of the different predicates is entirely parallel:

Here are some examples from the paper.

1a) saa=ts  ge   ra  |khii
    you=2ms DECL TAM come
    You (m) are coming.

1b) om=s      ge    (a)  kai
    house=3fs DECL  TAM  big
    The house is big.

1c) saa=ts    ge    (a)  gao-ao
    you=2ms   DECL  TAM  king
    You are a king.

1d) saa=ts    ge    (a)  Petru
    you=2ms   DECL  TAM  Peter.
    You are Peter.

1e) om=s      ge    (a)  nee.
    house=3fs DECL  TAM  this
    The house is this one.

1f) tii=ta    ge    (a)   saa
    I=1sg     DECL  TAM   you
    I am you.

1g) tara=di   ge    a  !nona
    women=3fp DECL TAM three
    The women are three.

1h) om=s      ge    a   tii
    house=3fs DECL TAM  mine
    The house is mine.