Many children worldwide fail to realize their potential for learning school mathematics. Diverse initiatives have been aimed at changing this situation, by using digital technologies to expand training possibilities and creating and disseminating new educational materials adapted to children's abilities. Most of these efforts focus on training that is adapted to individual children, however, and they draw the child’s attention away from the teacher and their peers. Here we introduce a novel approach to digital learning, applicable to groups of children who learn together by playing with concrete materials in small social groups, and who receive feedback only at the group level, encouraging discussions to arrive at consensus responses to math problems. The social groups (typically composed of 4 students) work within the classroom under an adult’s direct view. In a small-scale randomized experiment, we tested the effectiveness of such a program by comparing the math skills of children who played a set of math games in school, during part of the time reserved for math instruction, either in small groups or individually. When compared to a no-treatment control condition in which no games were played, no differences were found in children's mathematical gains, showing that the game play compensated for the shorter time of direct instruction that the children who played the math games had received. More importantly, the games played in small social groups with peer-focused interactive learning led to greater advances in children’s math skills than the same games played individually on tablets. Gains were especially pronounced for the children whose math skills were least developed, contrary to the concern that cooperative group play will enhance learning disparities because the most advanced students are likely to guide the group activities. Our results show that digitally controlled peer interactions enhance learning of pre-school and primary school mathematics for children at all levels and especially for those who started the intervention with the least mathematical knowledge. Digitally controlled games, played by children in small groups, therefore, promise to enhance children's mastery of the mathematical skills taught in primary school above and beyond the effects of the regular math curriculum and of digitally controlled games targeted to individual children.