Reciprocal of 142,857

Theorem
The period of the decimal expansion of the reciprocal of $142 \, 857$ is $6$:
 * $\dfrac 1 {142 \, 857} = 0 \cdotp \dot 00000 \, \dot 7$

Proof
Performing the calculation using long division:

0.000007000007...     -- 142857)1.000000000000...       1 000000         999999              1000000               999999              ---