A number string is an instructional routine that involves the teacher presenting a carefully designed sequence, or string, of related problems for students to solve mentally. Students engage in mathematical discourse as they explain their thinking, compare and explore connections between strategies, and justify their reasoning. Ultimately, the goal is for students to be flexible, strategic mathematical thinkers who have developed, rather than acquired, a range of mental strategies. Number strings are useful for student learning, but they also provide teachers with an opportunity to develop sophisticated instructional practices. In adopting this routine, teachers facilitate purposeful mathematical discourse, pose questions that elicit student reasoning and use mathematical representations to connect strategies and concepts. This workshop involves experiencing number strings as a learner, discussing mathematical ideas integral to strings and analysing string design – how you see problems being related