A large part of our common core standards includes students ability to look at a work problem, know how to solve it, apply a strategy and get the correct answer. With common core there is a large matrix of many types of problems first grades must master.
I have created a problem solving book which encompasses all the problems students must be exposed to. Each problem type comes with three application problems. One for direct modeling, one for student practice, and a change problem to expand their understanding with just right numbers. With my product students will be exposed to all the problem types listed in the common core.