Empirical research highlights the benefits for the development of children's mathematical competencies when they play linear number board games with dice and receive feedback. We, therefore, investigated mathematical competencies in two training studies with six sessions and a 3 × 2 design. The sample in the first experiment consisted of N = 79 German 5- to 7-year-old preschoolers and in the second of N = 64 German 6- to 8-year-old primary school students. Participants either belonged to a passive control group or played the board game House of Numbers up to number 20 (HoN-20). Some members of the HoN-20 group received specific feedback (e.g. 'well calculated'), while the remaining children received unspecific feedback (e.g. 'good'). Pre-posttest comparisons pointed to diverse effects: Playing the HoN-20 game and receiving feedback led to significantly greater gains in different levels of acquisition of basic arithmetic skills.