As a secular Jew who abhors mysticism being foisted off on people as an explanation for anything, but finds its history somewhat interesting, I can say a few words on gematria. At its simplest, gematria is just a number system, and we still use it in Hebrew today.
The word gematria is used in Hebrew, too, but it is Greek not Hebrew. Gematria is greek numerals (and a good deal more convenient than roman numerals, but I digress). We just ripped it off the greeks sometime around the 3rd or 2nd century BCE (or BC, if you're DMan). Since the Greeks ripped off the western Semitic alphabet (probably from the Phoenicians), I guess we can't be blamed for liking their mathematics so much.
Each letter has a value; add up the values of all letters in a word and you get the word's value (but see below). Letter values start at 1 for aleph (greek alpha), and count up. But when you reach 10 as yod (greek iota), you start going up by 10 for each letter. So the next letter cav (greek kappa) is 20. When you reach 100 as qof or qov (the letters no longer match greek), you continue by jumping 100s, so reish is 200; the alphabet ends with tav at 400 (there are 22 letters in all).
Normally you'd represent each number by the most "logical" short string summing to it, but there is no reason to do so. For example, my name is spelled aleph-reish-yod-aleph-lamed, so its numeric value is 242 (lamed is 30; it comes after cav). Whether or not you choose to connect this to the U.N. resolution with that very same number is your own business. Since 242 is also "bram" (a slightly archaic word somewhere between "but" and "now"), these 2 words are equivalent.
When larger numbers need to be represented, writing huge strings of the higher letters gets tiresome, so you can take low-order letters and re-start counting, starting with aleph = 1000 (500-900 are left alone); sometimes dots will be placed over such letters, but usually it's just left to context. For instance, the year 2000 is 5760, which is canonically he-tav-shin-samech, which isn't really a Hebrew word (the single letter values here are 5-400-300-60).
In practice, almost any smallish number is some Hebrew word, so you can have some fun. For instance, "wine" is "yayin" (yod-yod-nun = 10+10+50 = 70), and "secret" is "sod" (samech-vav-daleth = 60+6+4), giving new meaning to the Hebrew saying "wine in -- secret out" ("nichnas yayin yatza sod")...