I just got far enough to understand what you meant about houses being in the thousands.
I don't know how it works at other places in the country, but around here at least you typically have a central east-west street and a central north-south street (because everything's on a grid), and the numbers count out from there. So say Main Street runs north-south and is the central street for address purposes, and you have numbered streets that run east-west (1st, 2nd, 3rd, etc). If you're in the first block to the east of Main Street then the number part of your address would be 1XX - the XX standing in for the specific building number. If you're in the second block east then it would be 2XX. Often odd numbers are on one side of the street and evens on the other, so the address on the south side of 3rd street to the east of Main might go 101 E 3rd, 103 E 3rd, 105 E 3rd, etc. Then in the next block, the second block east of Main, they'd be 201 E 3rd, 203 E 3rd... The north side of the street would then have all the even numbers, so it'd be 102 E 3rd, 104 E 3rd, etc. On the west side of Main it would work the same way, but you'd be counting the other direction, and they'd be W 3rd instead of E 3rd. So you get to the thousands once you get more than 10 blocks away from the central street.
North-south running streets would work basically the same way, but north-south.
Some towns start off in the thousands, so like the first block would be 1XXX instead of 1XX, but otherwise would work the same.
It's a very systematic way of naming things that can be useful for navigating. If you tell me an address in town then just based on the address I have some idea of where it is, without any other information (especially if it's on a numbered street).