This paper studies the implementability of computational thinking (CT) among mathematics teachers by studying their pre-implementation practices of teaching CT. Based on survey responses (n=67), we report on analyses of what CT Danish mathematics teachers teach in their mathematics classroom, and with what mathematical subject areas they combine it. The study finds that more than 2/3 of the population teach CT, and that CT is taught in a wide range of mathematical subject matter areas. This is surprising since CT is not a mandatory part of the current curriculum, but could be amplified due to selection-bias. These practices are different from previous research results that have found CT relevant in relatively few mathematical content areas. This indicates a need for near future implementation strategy for CT in Danish compulsory school mathematics to address CT in a way with clear relevance for mathematics.