Two students in Danielle Adler’s kindergarten class at Marcus Hook Elementary School in Marcus Hook, Pa., prepare for an addition problem. Credit: Holly Korbey for The Hechinger Report The Hechinger ...

Re “Dismal student test scores deserve boos, not cheers” (Oct. 17): I taught sixth-grade math for 24 years and found that the biggest impediment to teaching at that level was that so many students had ...