Yeah my SO had a math teacher in middle school which had (as far as I can determine) decided she wasn't good at math. He didn't like those who weren't good, so he never helped her and even talked her down in class. As such she started to resent the math classes, and later on she avoided math, focusing on other things.
We met when she had her last year in high school, and she was unsure what to do for college or otherwise. She ended up taking a gap year to figure things out. I encouraged her to explore the options, and through a friend found she really wanted to do construction engineering.
To do that, she had to take a year to get some extra math and physics classes.
The start was rough, she had a fear of math and was lacking in basics like algebra. But she was determined to try. Meanwhile I'd been in college for a couple of years and gotten the basic math classes there for my CS degree. I enjoyed math, so tried to help her.
I quickly realized however I had to go back to basics and build some foundations. Back to basics with fractions, basic equation solving etc. After a few weeks of hard work from the both of us, and nearly giving up, things started to fall into place. She started to realized she could understand math, and with that it became a lot more fun.
After a couple of months, it turned out she was actually quite good at math! She picked up new concepts without much struggle, and my help was less and less needed. At the end of the year she passed the exams with high marks, and all I had done to help prepare was just to sit with her and check her answers as she went through previous exams.