The Kakeya conjecture predicts how much room you need to point a line in every direction. In one number system after another — with one important exception — mathematicians have been proving it true.

The average scores, from tests given last fall, declined 4 points in reading and 9 points in math, compared with tests given in the 2019-2020 school year, and are the lowest in decades.

Bianchini himself is suggested to have come up with the decimal point as a result of his travels, as he is likely to have passed through the Islamic world multiple times. This is where many math ...