The document summarizes research on the effects of a digital intervention on the development of algebraic expertise in students. The intervention involved students using a digital module for 6 hours over 6 parts. Testing of 324 students across 9 schools found that post-test scores were significantly higher than pre-test scores, indicating the module was effective. Additional factors that predicted higher post-test scores included previous knowledge, time spent in self-testing and summative assessment modes, and general attitude towards mathematics. The digital module included features like formative feedback, worked examples, and "crisis tasks" to challenge students' problem-solving strategies.