Knowing how to use your calculator well will help you in your final exam.
If you are studying for the IB and using TI-Nspire, go to Transum and work through the skill-a-day program. If you are using the Casio CG50 go here instead I also found this PDF you could download. Do not move on until you understand and can use each skill. If you get stuck put that skill into a search engine to find a good video or webpage that helps you better understand the skill. If you have never used a GDC before take your time.
If you are studying A-level maths, go to Transum and work through these skills. Do not move on until you understand and can use each skill. If you get stuck put that skill into a search engine to find a good video or webpage that helps you better understand the skill.
Try out your new skills at Transum. Click on the calculators to move from basic operations to more complex ones using a GDC.