Using the following numbers when using wrapping & grow will make containers and widgets scale beautifully on desktop, tablet and mobile. Works with any boxed container width (like 1140 or 1120 px or even %).
This is a working solution for 12 column designs (in the 1140/1120 grid). So if in your design an element takes up 4 columns then it should be 32%. The other one grows automatically making it easy to make layouts on multiple rows.