Robot toys can be used to promote STEM subjects, particularly coding and mathematics. The lesson described in this article illustrates how a robot toy was used with a number line to explore equality and missing addends in Year 1. The lesson progression models how activities can be sequenced to build on developing understandings while supporting the objective of balancing equations and equality. Extension opportunities and adaptation ideas are included to address technology availability and learners' needs at varying levels. The authors conclude that coding toys can be used to integrate mathematics and programming in engaging and innovative ways, to support young children in their learning.