Problem solving, which is the focus of the learning study reported here, plays an important role in mathematics The learning study was conducted in a Swedish grade 5 (Age 11) during spring 2012. The teachers’ definition on problem solving came from both Polya’s (1957) four principles (understand the problem, devise a plan, carry out the plan, looking back) and Mason’s(1984) three phases (entry, attack, review). From these, critical features were defined related to the object of learning. A learning study often develops teachers’ knowledge regarding the object of learning, and this learning study challenged the teachers to a great extent on their view on the focus of the teaching of the object of learning. The focus changed from training problem solving via solving problems into a focus on the process of problem solving, preparing pupils to solve problems. In the first developed pre-test the teachers tested the pupils on solving problems and the only insight they gained was whether or not the pupils’ mathematical skills were sufficient to solve the problems. In what way the problems were solved, what strategies the pupils choose from, if the pupils understood the problem and reflected on the answer afterwards, was not possible to depict in that test. The pre-test was revised where the focus was on the problem solving process rather than on solving the problems. For instance; the pupils were asked to choose between given strategies and to distinguish between important and unimportant information within the problem. The phases described through the critical features were possible to discern by keeping the context of the problem invariant and by varying the question to the problem. Issues regarding the phases were discussed and asked for, and as the focus was on the process of problem solving, the problems did not necessarily need to be solved. For teachers and teacher educators this study illustrates a way of teaching problem solving, where the focus is on the process of problem solving. In the presentation the insights the teachers gained regarding the focus in lessons on problem solving will be illustrated through the two pre-tests developed and through the changes made in the lesson plan. Clear examples of the use of patterns of variation will be given and related to the discernment of the object of learning.