I was that kid and still struggle with math. Even with two different tutors, I am completely unable to grasp certain aspects. Thank goodness common core math was introduced after my daughter was almost done with school.
My son mother is the same, she got lost with math when they hit fractions. She never caught back up. Math just locked up her brain.
When mine was little, like me we have Aug birthdays, and with that the option comes with do we start him early or late.
I asked my father why he started me early, he said I started you early because if you failed it would most likely be early in your education, and most likely no one would remember and tease to about it. He said put him in school.
A few years later while at Lettie Dent, we realized he wasn't being taught math tables, cursive writing, dealing with money/giving change and a few other things.
We spent maybe 15 to 25 min a night working with him and it paid off shortly. We used other members of our family that had higher education than either of us when we hit road blocks and didn't know the answer or the correct route to get where he needed to be.
High School math questions were answered by my Uncle, nuke engineer or his son professor at Carnegie Melon, along with two BIL that were Navy Academy Grads. They all were a huge help.
Kids like the elderly need an advocate.