I'm reading Chris Pines 'How to program' This was the latest concept,
Length:

"Another string method is length, which tells us the number of
characters
(including spaces) in the string:
puts 'What is your full name?'
name = gets.chomp
puts 'Did you know there are ' + name.length + ' characters'
puts 'in your name, ' + name + '?'
What is your full name?
Christopher David Pine
#<TypeError: can't convert Fixnum into String>

Uh-oh! See? There it is! It”Ēs an easy mistake to make. Anyway, ifyou didn”Ēt know to be on the lookout for this error, you can still
figure
that the problem must have happened sometime after the line name =
gets.chomp, since I was able to type my name. See whether you can
figure it out.
The problem is with length: it gives us an integer, but we want a
string.
That”Ēs easy enough; we”Ēll just throw in a .to_s (and cross our fingers"

I don't see the problem with the computer giving us the integer version
of the number of characters? He then asks us to create a program
that will ask someone their first/middle/last names individually and
then add them up after. I would think to just ask for them using GETS
and then add up the lengths using the .to_s conversion.. but surely what
I've learned about strings is that you cant add them together right?

Can anyone explain this?

Kind regards

Josh