The ultimate Calculator has to be WolframAlpha which as you can see has a page of its own with several slideshows to help you learn how to use it.
For drawing and exploring graphs, use the outstanding Desmos Graphing Calculator.
A series of pages on Tools provide links to resources for the classroom such as GeoBoards and many simulations.
A series of calculator pages provide information and resources on calculators. The pages in the series:
- Casio fx-85GT Plus & fx-991ES PLUS
- Casio FX991EX-Classwiz
- Casio Graphical Calculators
- Texas Instruments
- Mathematics for Students – Calculators
- Use of Technology – A Level
Some highlights from these pages…
The collection includes manuals from Casio and Texas and also some very clear guides from Dr Frost.
There are some excellent step by step instruction videos on using the Casio FX991EX calculator.
MEI have many tasks for older students using Casio Graphical Calculators (they also have tasks using GeoGebra and Desmos).
On the Mathematics for Students pages you can find everything from a game to help students understand order of operations to a Normal Distribution Calculator.
The pages in the series: