How do I use string manipulating functions, to pull numbers out of strings and add them together?

 Two variables store strings that consist of a letter of the alphabet, a blank space, and a number (in the form ‘R 14.3’).  Write a script that would initialize two such variables.  Then, use string manipulating functions to extract the numbers from the strings and add them together

[Walter Roberson]

duplicates http://www.mathworks.co.uk/matlabcentral/answers/121969-se-string-manipulating-functions-to-extract-the-numbers-from-the-strings-and-add-them-together