Thank you for recognizing this and trying to help your daughter with it!
I was in the "gifted and talented" program and honors classes in school and definitely feel this. But I also felt it then because I was good at some things and terrible at others. I learned to read and write when I was 3 years old and was always off the charts in reading comprehension and those types of measures - but I always struggled with math from the time we got introduced to multiplication tables onwards. My brain just does not compute math. Whenever teachers looked at my notes (because you had to "show your work"), they didn't understand what I was doing because I didn't understand how to do it. And yet I was always put into honors math classes, because if you're an honors kid you get put in honors everything even when it does not apply.
So I'd feel like a little genius in English class and a total failure in math class. When your whole identity has been built on "being good in school," this really does a number on you.
I'm glad you are supportive of your daughter. My parents just tried to drill multiplication tables into my head and when I couldn't memorize them, got more frustrated with me than I did myself because I had never struggled with anything in school before and they weren't prepared for it. I never got praise for my report card full of A's and B's and instead got condemned for the C I got in math.