Scientific calculators designed for educational market became more powerful due to competition, so in the earlier years of 1990s, Sharp decided to make a new EL-531 version used a simplified variation of the AER system, which make possible of entering expressions in the same way as written on paper. The new EL-531G (button cells), EL-531GH (AA batteries) models were built from 1992, and used the new Direct Algebraic Logic (DAL) system, which displays only the last pending operation, make more difficult to check longer expressions. Casio skipped this step in the evolution of the fx-82 series, and introduced the full-function formula processing capability with two-line display in the second half of the 1990s.

Igor