Dr. Pickover asked, “What kinds of numbers did Jesus use (or someone of his era)?”
Since it’s claimed he spoke Aramaic, I expect he’d have used the Aramaic/Hebrew number system where their alphabetic characters also served as their numbers. (The languages, of course, also had names for the numbers, just as we have “1” and “one”, etc.; I’m just referring to how numbers were written.) Since some of the apocryphal and pseudepigraphic infancy gospels tell tales of his having discoursed on the symbolism of the Greek & related alphabets, one might also argue that he could have written using the Greek number system, which likewise used its alphabet for numerical digits. If you consider the text of the “New Testament” as definitive, all numbers that appear in passages with references to Jesus in the four gospels are written out in Greek (e.g., εἷς/μία/ἕν [one], δύο or δύω [two], τρεῖς/τρία [three], τέσσαρες/τέσσαρα [four], ἕξ [six], ἑπτά [seven], ὀκτώ [eight], ἑπτάκις [seven times], ἐννέα [nine], δέκα [ten], εἴκοσι πέντε [twenty five], τριάκοντα [thirty], ἑκατόν [one hundred], ἑβδομηκοντάκις ἑπτά [seventy times seven], δισχίλιοι [two thousand], πεντακισχίλιοι [five thousand], etc.) Most numbers in the text tend to be written out, though there are a few exceptions: e.g., the infamous “666” of the Apocalypse is written with the three Greek letters chi (χ), xi (ξ) and the antiquated stigma (Ϛ); in the Greek numeral system, the letter χ has a value of 600, ξ 60 and Ϛ/Ϝ a value of 6, so that the three letters appearing together as a number have the combined value of 666. (See also the article, “Arithmology in the Bible” ).
Further, he asked, “Do you think he could multiply?”
It would be hard to say, but perhaps the text can be taken in support with passages such as:
λέγει αὐτῷ ὁ Ἰησοῦς· οὐ λέγω σοι ἕως ἑπτάκις ἀλλὰ ἕως ἑβδομηκοντάκις ἑπτά.
dicit illi Iesus non dico tibi usque septies sed usque septuagies septies
Said Jesus: To you I say not ’til seven times,’ but ‘until seventy times seven.’Matthew 18:22
While both seven & seventy can have symbolic meanings, the passage may not be literal, but nevertheless it is an example of the idea of multiplication—though I don’t think it really makes it clear whether he or his listeners would have been able to give the answer.
Having also asked why 0 wouldn’t have been used: neither the Hebrew, Aramaic nor Greek number systems had a character representing the number 0, as it wasn’t needed by non-positional number systems. There’s a whole section on the emergence of zero in Ifrah’s The Universal History of Numbers: From Prehistory to the Invention of the Computer, if I recall correctly.