Divided by 7

Divided by 7

7 is a special number, and it is a headache to calculate the small value divided by 7. In fact, the calculation divided by 7 contains a very simple law. See:

1/7 = 0. 142857142857... 2/7 = 0. 285714285714... 3/7 = 0. 428571428571... 4/7 = 0. 571428571428... 5/7 = 0. 714285714285... 6/7 = 0. 857142857142...

Is there a rule? 1/7 = 0.14, 28, 57. The number behind is exactly twice that of the previous one, 28*2 = 56, and 56*2 is 57 just in one place. However, the following sections 2/7, 3/7, 4/7, 5/7, and 6/7 are exactly the segments in this string, but the starting position is different. Therefore, if you remember the 142857 string, you can easily calculate all the values divided by 7.

In high Sinochem, this rule is very useful. There is a theorem that the volume of one molar of any gas is close to 22.4 litre. While 22.4 = 3.2*7, 3.2*10 = 32 = 25, in calculation, the 3.2 factor is easy to get about, and know the rule divided by 7, this kind of computing often becomes very fast.