Convert a string value from a T-SQL table in float values and store them in a second TSQL table

I have a TSQL table from which I need to copy a column in a second table. The values that I need to copy are stored in the format 4444.44434.4344.4434.4224 as a string But first I have to convert the values to 4.444 as a float. Then I store the values in the second table.

Now I do not know exactly how to read the values from the first table and then store them it in the desired format in the second table.

I am very grateful for any solution.