User stories with multiple approaches

Hello,

I've a simple User Story for a shop:

As an Employee
I would like to
- retrieve the weight of the buyer's purchased product on my cash register
- associate it to the right product

In order to:
- calculate the price
- reduce the product's stock by the bought quantity

That are multiple ways of doing this:

1) Let the employee weight manually the product and introduce the weight manually on the cash register