The meaning of the is defined for you right there in the problem. It's basically a new abstract binary operator. You could also think of it as a function with two arguments: the number on its left, and the number on its right. Does that help?
you are very good , thanks very much again , i was completely lost , have to do a test that includes few models - maths , history , etc and i just got totally mixed up with everything ... ,
is that the right thing to do