The Swedish government has recently introduced digital competence including programming in the Swedish K-9 curriculum starting no later than fall 2018. This means that 100 000 teachers need to learn programming and digital competence in less than a year. In this paper we report on our experience working with professional teacher training in Sweden's fifth largest city. The city has about 150 000 inhabitants and about 50 schools with about 14 000 students in primary education. The project has been carried out in close cooperation with the municipality.

The work started in the fall of 2014 with a pilot study with 10 teachers in different subjects that was carried out during spring 2015. The pilot study was successful as the teachers were able to introduce activities related to programming and computational thinking in their subjects after only two half day workshops. The next step was to scale this up to include all the schools in the city. As expected, this turned out to be a larger challenge. More than 70 teachers were involved in the second part of the project. Some of the lessons learned are that it is quite easy to provide teacher training, but harder to get teachers to actually change their teaching and even more challenging to get teachers to help their colleagues introduce programming or computational thinking in their teaching.

Based on our experience we draw some general conclusions and make suggestions for how to scale up the teaching of programming and computational thinking to all.