Help with formula column

Help with formula column

I have a numerical entry in an existing column and I want to simply provide a True or False statement to a formula column.

Example - this is what I have

                      Name            Number
Row 1            Smith            10
Row 2           Jones           45
Row 3           John            98
Row 4            Mable          110

Example - this is what I want

                     Name       Number         Formula
Row 1            Smith            10                     False
Row 2           Jones           45                     True
Row 3           John            98                      True
Row 4            Mable          110                     False

So I want to recognise where the "number" is between 11 and 99


What formula would I need to use to enable this?