Algebraic thinking often requires generalisation processes. Generalisations of patterns are one frequently used design in early algebra settings in research and practise. Symbolical letter variables are not common in primary school and actually not needed by the children to articulate their pattern generalisations. Nevertheless, from a research perspective it is interesting to explore children’s spontaneous interpretations of letter notations. The reactions of 3rd-and 4th-graders, who participated in an explorative study presented here, might provide a starting point to sensible appreciate the individual thoughts and ideas about letter variables in further studies.