The example in the question is:
> For example, if we choose two 2s, zero 3s, and one 5
That's talking about "zero 3s", not "three zeroes".
In this context "zero" is not a noun, but an adjective.
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In addition, see the adj. definition of zero: https://www.oed.com/dictionary/zero_n?tl=true#1209971660
The example in the question is:
> For example, if we choose two 2s, zero 3s, and one 5
That's talking about "zero 3s", not "three zeroes".