Algebraic thinking is the activity of doing, thinking and talking about mathematics from a generalised and relational perspective. The traditional teaching of algebra, with its sudden introduction of pro-numeral symbolism and limited support to understand the meanings underpinning these letters, has been shown to confound many middle school students. One alternative approach is to introduce students to algebra through problem-solving tasks. Working on, representing and solving structurally related problems in a variety of ways can help to prepare students to think algebraically. This article reports on a research project that aimed to develop students' algebraic thinking through a generalised and relational perspective of mathematical problems.