Error doing sums on queries

[danicort01]

Hi, so im having some trouble trying to do this query where I want to sum all my bought and selled products to customers, and then subtract this to to know how many i have left, but when i do it for some reason 1 or 2 of the 3 columns is being sum and at the same time multiplied by 2 or 3 for no reason this keep happening and i dont know how to fix it, please help. If you chek the images I bought 5 of the product number one but the sum is showing 10 and i also bought 6 of product number 2 and is showing 12, on the other hand I bought 20 of product number 3 but this one is the only right one. (image 1 is showing how I did my query, image 2 is showing my bought quantity by products, and number 3 is showing me what the query shows after the sum) I speak portugues and also spanish if for somebody is easier to answer me the question, thanks a lot group

[orange]

Danicort01.
consulte este link
See this info from Allen Browne.

Você pode escrever sua postagem em seu idioma nativo (português) e usar o Google Translate
para criar uma versão em inglês para postar no fórum. A tradução é mais do que adequada
para comunicação na maioria dos casos.

Boa sorte com seu projeto