If it's needed to sell a smaller amount of a product from a bigger pack there must be done some settings first. Go to
Stock - Stock-in-trade - Edit and find the product

When the correct product is found, we need to do a setting on the group. "Sell as" should be set to Broken package. In this case all products in the "V-mærket" group can now be sold as a broken package.
The details and the setting for the group can be entered by pressing F4 when the cursor is in the Group field. Remember to press "Update" when done.

Now we must do some setting on the specific product.
1. Multi 1 will show the amount we want to sell. In this case 1 unit.
2. Number shows the amount in the whole package. In this case 4 units.
3. Stock type must be set to amount.
4. Pay for must be set to amount sold.

Next time I want to sell 1 unit of the 4 units package it will look like this and the price is corrected.