Did I just get scammed by the CG50?

I'm just gonna keep this short because I'm hot and bothered as I can imagine you all are too. How do I use the CG50? I've just started A Level Maths and Further Maths a my school recommended me to get the graphical calc (Casio FX CG50) but when I asked my teach about it he said just to stick to the FX-991EX (The regular one everyone uses for A Level Maths)