Temperature is estimated to be 21.2oC. The last 2 is uncertain.

The temperature 21.2oC is expressed to 3 significant figures.

Temperature is estimated to be 22.0oC. The last 0 is uncertain.

The temperature 22.0oC is expressed to 3 significant figures.

Temperature is estimated to be 22.11oC. The last 1 is uncertain.

The temperature 22.11oC is expressed to 4 significant figures.