A prefix expression tree showing an expression can be supplemented to also display the expression in infix notation. In one embodiment, the present invention includes displaying an expression being capable of representation in infix and prefix notation in prefix expression tree format. In one embodiment, the expression includes a plurality of operators and operands, and the plurality of operands make up the leaves of the expression tree. In one embodiment, the present invention further includes inserting a plurality of infix operators corresponding with the plurality of operators into the prefix expression tree, wherein, the plurality of operands and infix operators represent the expression in infix notation.