Problem solving is not just a word problem. If a word problem is in a lesson on addition, many of them use addition. NO THINKING REQUIRED! Math is not just manipulating numbers, working equations, etc (although that is part of what I love about math). Math is CRITICAL THINKING/PROBLEM SOLVING. Math is taking what you know and using it to find the answer to something that you do not know.
I repeat - PROBLEM SOLVING IS NOT JUST ANOTHER WORD PROBLEM. IT IS WHAT YOU DO WHEN YOU DO NOT KNOW WHAT TO DO.
So many people equate word problems with problem solving. They are not the same thing!