# How to use the solver with a constraint on multiples cells?

I want to minimize this function in LibreOffice Calc:

```
f = 5*x1 + 3*x2 + 2*x3 + 0*x4
```

With respect to this constraints:

```
A1 < x1 < B1
A2 < x2 < B2
A3 < x3 < B3
A4 < x4 < B4
x1 + x2 + x3 + x4 = 1
```

I want to use the solver to resolve this problem. I can easily do it if I only care about the 4 first constraints. But I don't know how to implement the last one. An idea?