Being precise is not what Russians are very good at. Moreover, Russians do not expect a strict level of accuracy from anyone. Only big numbers matter, only big changes are noteworthy. Nobody cares about slight variances.
In everyday life, Russians are used to being rather generous than being precise. For a person who is too concerned with the accuracy of numbers, there is a special word in Russian “зануда” (sickener). Being too meticulous can be considered as lacking imagination and discourtesy. For example, I (often) like meet with my friends in a cafe. During my whole life I have never seen any of my Russian friends calculating tips. We tip as much as we think is enough, as any precise calculation would be offensive to anyone. Smartphone applications like a “Tip calculator” seem extremely weird to Russians. If anyone ever tried to calculate their share, he would be considered unbelievably stingy and a “зануда”.
Rough approximation is normal practice in business life. As a reporter, I have to arrange interviews with large (and not so large) market players. When I ask about sales growth figures, for example, I often get responses like “well, there is some slight growth, up 30% or 40%”. A range of10% is fine for Russian sources, so there is not a big difference between 30% and 40%. Sometimes, in the booming markets, the response can be “up to two, three times”. The difference between “two times” and “three times” is one hundred percent, but when changes are so significant, the scale is magnified, so such responses sound reasonable to me. My sources are usually in pretty high positions, who have an access to precise numbers, but they do not think they need to bother about statistics within a one-percent precision. Of course, when it comes to official earnings reports for shareholders, the numbers are accurate, at least, as precise as they should be according to international business standards, but in all other cases, some approximation is quite acceptable and even appreciated. Another good example is the recent census in Russia. The Russian press reported that about one or two million (!) people or even more were left out during the 2010 census.
The Russian language reflects this attitude towards numbers and being precise. When one wants to report hard-and-fast numbers, the word order is like this: “Здесь пять килограммов сахара” (There are five kilos of sugar here) or “Дорога длинной восемь километров” (The road is 8 kilometres long). But if the numbers are not so important, the word order should be changed to “Здесь килограммов пять сахара” (meaning that this is only approximately 5 kilos of sugar, actually somewhere in between 4.5 and 5.5) and “Дорога длиной километров восемь” (may be seven, may be nine). By placing the unit of the measurement (kilogram, kilometre, byte, whatever) before the number, you indicate that you are not sure or don't care about the accuracy, and you suggest only approximate numbers / measures to your interlocutor.
In the store, you may often hear “Мне граммов триста сыра, пожалуйста” (about 300 grams of this cheese, please). You may think that the buyer doesn't know how much cheese he or she wants to buy, but this is not true. This is just a polite way to communicate with a seller, a way of not appearing too parsimonious.