Casio Fx 991 Es Calculator By Steffan Willis on Apr 12, 2009 - Updated Oct 15, 2011

This calculator is vital for any student who has to do relatively complicated maths frequently as it is powerful and intuitive. It has a wide range of functions with an easy to use "Natural Textbook" display.

Functions

It contains all of the functions you would expect for a scientific calculator: logs, trigonometry, recall functions, powers, etc. However, it also contains functions that many other similar priced calculators do not, e.g. numeric integration and differentiation, base-n calculations, advanced statistical techniques, function tables, equation solving capabilities, matrices and vector calculations.

One of my favourite aspects of the calculator is the 40 pre-programmed scientific constants, which are especially useful for physics calculations.

The statistical display is also worthy of note as it allows you to enter the data in the form of a table and so you can review the data and thus minimise typing errors. Also important to highlight is the fact that the computer can do numeric integration rather than algebraic integration as this is banded in most exams, however this function does allow you to check your results extremely easily just by entering 1 into the equations/calculator and the answers should match.

My only criticism is that it does not contain a graphic function, but you get what you pay for and for the price it is an excellent calculator. And is perfect for both university and high school students.