Rounding quantities

[eporedieis]

Hi, I'm new in Prestashop. I'm creating a new template for a little shop but I have a big problem.

I have to sell products that are in boxes, so I need to round the user wishes quantities to boxes.

 

I think I need two values to do this: the input quantity and a variable with the quantity-per-box of each product (defined in the backoffice). If the first is 10 (square meters) and the second 1.5 (square meters / box), I need to do 10:1,5 and round the result to the unit (6,67 become 7). Multiplying 7 (boxes) for 1,5 (square meters / box) I have 10,5 (sq.m), that I can now show in a label.

 

But... I don't know how to do this and I've found no topics about this!

 

Anyone could help me please? Thanks!

Edited August 18, 2013 by eporedieis (see edit history)