With smaller families, the kid density in neighborhoods means fewer pick up games. People decry all of the organized sports kids are playing these days, but face it, it's gonna be organized to get enough kids together in one place to play some sports.
During the summer, my young adult sons regularly play pick up games of baseball (hardball) in the city, where they live. Basketball is the game of choice for most city kids these days.
Where are all the kids playing street hockey? I don't see it in my bucolic little corner of the country.
My sons played it some, as well as many other sports, both organized & pick up games.
As to the article, mention of binomial theorem, don't know about the rest of the nation's schools, but I know I had to relearn trinomials to help my sons with their homework. Then again, I had a recent conversation with one of my sons about converting numbers into various numeric bases. During the drive between my house & the store, I taught him how to convert numbers into base three, base eight & then some others which were higher than ten. Learning can & does take place outside of school...
I only learned numeric bases after I bought an M1 Garand. You have to know your octets to know how many rounds fill how many clips. Finally I understood.
Where are all the kids playing football in vacant lots?
I live very close to a small inner-city community in NJ. I'm always astonished at the poor, black kids who still gather in dusty, empty lots to play ball and other games without any parental or adult supervision. It's like the 1950s come back to life.