Abstract Doing mathematics still remains a challenge for non-sighted students. Communicating with their sighted peers or teachers while doing math also presents difficulties since they use different representation supports. Interaction on accessible mathematical interfaces has had promising results in browsing using braille and audio, but support for doing math requires further development. To date, there aren't many options regarding accessible support for manipulating expressions as it is regularly practised in the learning stage. We have carried out an experiment with sighted and non-sighted students with the aim to better understand the actions they perform while solving basic algebraic expressions, in order to design the interaction in a multimodal interface for doing math. Sighted and non-sighted participants solved four algebraic expressions orally, and sighted participants solved them in write as well. The results showed that the intentions of the participants were in conformity with the systematic application of algebraic rules, regardless of visual ability. It is suggested that success in the interaction design of the interface will depend on the degree of direct access to the expression terms, and the ease of use of features intended to minimise memory load