Stress?

Common elementary math textbooks in the U.S. cover almost twice as many topics per grade as do Singapore’s. As a result, math textbooks in Singapore expect students to complete about one thorough lesson on a single topic per week, while U.S. students are expected to complete about one lesson on a narrowly focused topic each day.

Everyday stress after stress after stress.
                     -or-
Four High Stress Tests a Year

Hey, I'm still good with the Opt-Out.

In Singapore, schools use a national examination to identify upper elementary grade students who are having difficulty in math. Those students then receive
special instruction based on an adapted curriculum framework taught by trained Mathematics Support Teachers. Importantly, they also receive about 30 percent more math instruction than their peers so that they can cover the same rigorous content, only at a slower pace.