We consider using the slide rule.

In the previous article we talked about the appearance slide rule . However, each new achievement is usually accompanied by some losses. The situation is the same with the slide rule . The ruler allows you to make calculations much faster and more conveniently, but there are losses. When using logarithm tables, you do not need to determine the position of the decimal point yourself; it is already indicated in the table. When calculating the ruler, you will have to determine the position of the decimal point yourself.

In order to determine the position of the decimal point, it is necessary to roughly estimate the answer to the problem being solved. For example, we evaluate the expression that was considered earlier:
(194.768x0.045x19.22) :( 1,558x35.4).

We round the numbers of this expression and get: $ (200 \ times \ frac {1} {20} \ times 20 ^ 2) :( 1 \ frac12 \ times 35) $, which is (4000: 50), or 80. This means that the answer we get by solving the above expression exactly will be closer to the number 80 than to 8 or 800. Thus, we estimated the position of the decimal point, or in other words, the “order of magnitude” of the future answer.

Now, using a slide rule , you can perform the specified actions. As a result, we get the answer 587, and since we know that the answer should be closer to 80 than to 8 or 800, the decimal point can be safely placed after the second significant digit to the left, that is, we get 58.7. All calculations using a slide rule, including the determination of the order of magnitude, will take an experienced person just 35 seconds, if you take it slow, so as not to make mistakes. If you solve this example, producing multiplication and dividing by bar , you can get a more accurate answer. If you do this calculation, you get 58.6. But it can go as much as 20 minutes, if somewhere else in the calculations make a mistake, the probability of which is very high.

This tool will help you even when building or compiling project house Irina , you can quickly calculate the area of ​​each floor, the number of bricks for the walls and much more.

Modern pocket calculators and computers, of course, have simplified all possible calculations even more.

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