You only pay one month, and then after that you can either choose to renew it or cancel it.
$4680
Since 18% is 18/100 you just have to multiply the $842.4 by the reciprocal of that to find your answer
Reciprocal of 18/100 is 100/18
842.4* 100/18 equals 84240/18
84240/18 equals 4680
Bro that's a lot, i don't know what the heck you are talking about.
The answer is 0.0136986301369863
Hope this helped!!