The blame should be put squarely on the shoulders of tophatter.com. They know the quality of what is being sold and choose to look the other way for the sake of making commission and sales fees on these imitation goods. In my estimation and also the interpretation of the law this is outright FRAUD.
Inverse operations are opposite operations that undo each other. Addition and subtraction are inverse operations. Multiplication and division are inverse operations.
Most equations are harder to solve and you have to simplify the equation before you can see the solution. One way to do this is to use inverse operations. An operation is, for example, addition, multiplication, division and subtraction. An inverse operation is an operation that reverses the effect of another operation.