Cardo as Pivot and MILIA as plural noun

Latin Learning Latin
1

My book says that Cardinal Numbers are pivots in the languge
because the other numbers are derived from them and pivot
around them.

Is this simply an artistic statement that when you use ‘QUARTUS’
it came from ‘QUATTUOR’ or is there some grammar meaning
to this like using different cases and tenses?

Also, MILIA or the word ‘Thousand’ is an adjective. This makes
perfect sense

Example: A thousand men

But why is it a noun in the plural?

Is this an example of it as a noun in the plural: ‘There are thousand
of men.’ You can say:

The thousands

which means it is a noun whereas you could not say
The A thousand


Thanks.

2

We saw thousands of cars. – ‘thousands’ is functioning as the direct object of ‘saw’ and is a noun.
We saw a thousand cars. – ‘cars’ is the direct object of ‘saw’ and ‘thousand’ is functioning as an adjective modifying ‘cars’.
Latin ‘mille’ and ‘milia’ work the exact same way.

Don’t worry about it too much, just understand the difference between cardinal and ordinal numbers and know how to recognize them.

3

Just out of curiosity is the sentence, “We saw the thousand cars” is
‘thousand’ a noun or an adj or both or is it ungrammatical to say
it as a noun?"

Thanks.

4

“We saw the thousand cars” thousand is an adjective, compare:

We saw the thousand cars.
We saw the big cars.
We saw the new cars.
We saw the red cars.
We saw the thousand big new red cars.

All are functioning as adjectives modifying ‘cars’.
However, notice the following:

We saw the thousands cars. – grammatically incorrect
We saw the thousand of cars. – grammatically incorrect

words like ‘thousands’ ‘hundreds’, ‘millions’ function as nouns, but a/the/one thousand or hundred or million function as adjectives.

5

Can i take this as a golden rule that if you put ‘a/the/one’ in front of
thousand it functions as an adjective?

What if you put a/the/one in front of the plural thousands?

Thanks.