With louder and more widespread calls to include computer programming as a core element of school curriculum, global efforts to define innovative and distinct coding curricula are underway. We take a different tack in this paper, one oriented by an investigation of the common ground between learning to program and learning mathematics. We observed 9-and 10-year-olds as they learned to build and program Lego Mindstorms EV3 robots over 4 days, attending in particular to the ways that programming robots to move might support the development and integration of powerful instantiations of number, arithmetic and multiplication. Our findings suggest that children's understanding of number, and their transitions from additive to multiplicative thinking, can be powerfully supported by engaging in practical tasks rather than practice exercises. Keywords Robotics. Coding. Elementary mathematics. Instantiations of arithmetic. Metaphor. Video analysis Worldwide, coding is gaining momentum in K-12 education. Estonia and England, for example, have implemented national curricula, making computer programming mandatory for all school-age students across all grades. Other nations 1 are also moving in this direction. In North America, while national-level discussions and calls have yet to gather the same momentum, an increasing number of initiatives are emerging at the local level. For example, the Chicago School District recently launched Computer Science for All, making computer science a core subject in all public high schools. This