I studied with several people who got to be on half a million or more, they weren't great at maths. Of course I exaggerate a bit when I imply they couldn't manage everyday arithmetic, but some of them were really limited. One of them never managed to get a calculation right the moment a Greek letter was thrown into it, he was like a rabbit caught in headlights. As it turns out, he was the most successfl of the lot.
Oh sure, not saying they didn't have something going for them. I had this rugby mate, former Army guy, came back from Basra and did a few courses to help him get a top job. His mathematical or investment nous was limited but the gravitas, poise, cockiness and leadership was definitely there. He could sure schmooze people into certain big money investments, but I can guarantee you he didn't really understand them.