I will simulate what i need to achieve.

for example, i want that **`#2`** took the whole space, remaining of `100% - 180px`.. how to achieve that?

[![enter image description here](https://i.imgur.com/7X6hdHF.png)](https://i.imgur.com/7X6hdHF.png)

p.s. seems `flexbox` is more supported over devices than `calc` - <http://css3clickchart.com/#flexbox>