I have found the way:
- view-> selection inspector In the selection inspector,
- current object: (select the grid you want to visualize)
- selection Type: Threshold
- Field Type: CELL
- scalars: (select the cell scalar to visualize, in my case: density)
- Add Thresholds -> Lower: (set your value) Upper: (set your value)
- Display style->Cell Label tab Visible; Label Mode: (select the cell scalar to visualize, in my case: density)
Now you are done!