They do need to teach how things apply. I used to have my daughter get my fabrics cut and pay for them while I browsed in the same store. She must have been about 8 at the time and to bolster math skills, we showed her how to count and add back money, showed her how to measure, and the like. Also taught her to bake so she would learn how to measure.
I had just given the kid money and fabric with instructions, and a lady watching this asked me how old kid was.
Lady said she taught junior high math and most of the students had no idea.
My mother had me do the same as a child, so I saw nothing unusual in it.
Algebra- I have never used it. Passed the classes and remember nothing. I do use geometry.