To determine the type of code. They are linear (sequential reading) and two-dimensional (information is read vertically and horizontally). Most popular shops are linear codes with a European code system, they can be read with inexpensive scanners. The most popular EAN13 - thirteen numbers. There is also a short code - EAN-8. But in this case the first two digits indicate the country-manufacturer. The two-dimensional code can be read with a special two-dimensional barcode scanner, to the naked eye to calculate the country-manufacturer is impossible.
The list of codes is too large to memorize, and it should cut out and save. It is worth remembering that Russia's fixed prefixes from 460 at 469, but is currently used only 460. There is a formula that allows you to check the authenticity of the bar code. Need to add the digits standing in the even places and the sum is multiplied by three. Then add up the figures standing on odd places (of course, without the last check digit). Add these two amounts, to discard dozens. Out of ten, subtract the resulting number. Should get the figure that in the barcode is the last.
Globalization intervenes in the economy, making the separation of the country of manufacture is extremely conditional. Digit barcode may not match the information on the product packaging, and product, and the barcode can be genuine. If the packaging says "made in China", and the seller chirps of the incomparable American quality, not worth it to confront him ahead of time, because the manufacturer can't get the code at the place of their actual check, and the place of the country where the main export flows (e.g. in Russia). The second point - the legal niceties of licensing and ownership, especially clothing and gadgets. The product can be produced in subsidiary company at any point of the globe (or rather, where labor is cheaper). Well, the most elementary, the founders of the company-manufacturer can be representatives of different States. Who have a stake in thicker, and he selects the prefix in the barcode. So that figure is, in General, the meaning of fiction and abstraction, important mostly for economists and lawyers and less for ordinary buyers.