Expanded

The Expanded widget is used to give a child widget the flexibility to expand and fill any remaining space within a Row, Column, or Flex widget.

For example, if we have a Row widget with two child widgets, and we want the second child to take up any remaining space after the first child has been given a fixed width, we can use the Expanded widget for the second child.

Row(
  children: [
    Container(
      width: 50,
      height: 50,
      color: Colors.red,
    ),
    Expanded(
      child: Container(
        height: 50,
        color: Colors.blue,
      ),
    ),
  ],
)

In the above example, the first child has a fixed width of 50, and the second child is wrapped with Expanded widget, which makes it fill the remaining space in the Row widget.