Math was my horror subject in university. No matter how much I practised, I always made the same stupid mistakes. I barely passed my second attempt. When you're at home and take your time to go to each step slowly, when you check if you're right inbetween, then it works out. But when you're at the exam, with a time limit and when you have to calculate everything by hand without the chance to triple check your answers. Then you're screwed.
Who in this world needs to calculate by hand. When I do math in my job later then I am using calculators and excel sheets. When there's something I don't trust, then it's my ability to do math right.
Anyway, I recommend watching
numberphile on YouTube. It's a channel about math related stuff. Like I said I'm a complete fail, when it comes to math, but this channel is awesome. And for that matter watch
signingbanana as well. It's the channel of Dr. James Grime. Math professor at Cambridge University. He's great and funny and cute. There are other channels like ViHart, which are cool to watch as well.