[gdfer]

I wouldn't make math/STEM a special emphasis when they're young.

It's more important to foster an positive learning environment and encourage/draw out curiosity and creativity at this age. Help them become curious about the world, fascinated with what they're learning and find enjoyment in learning.

In terms of subjects, aim for a strong reading focus at an early age as it will pay dividends in all other subjects (even math) if they can read/comprehend well.

[sekou]

Salman Khan's One World Schoolhouse does a good job exploring this topic I think. On the one hand many students struggle with what he calls a "swiss cheese" understanding of math: lacking mastery of fundamental concepts that leads them to struggle as they grow older. On the other hand he advocates for a more holistic approach to learning overall from the beginning, exposing children to various subjects and exploring how everything is connected.