[wolfi1]

make a little game at the cash register in the supermarket: if he can calculate the right sum of the price he gets a fiver, if he can tell how much change you have to prepare he gets a dollar. for the first thing he needs to memorize the prices and add them up, for the second one he needs some sort of modulo calculation. so there are several ways to incentivize the use of math in everyday situations

[xyzzy123]

Right; most kids won't be very interested unless they're around other people who seem genuinely interested. They key their learning effort off perceived relevance. Perversely, bad school environments can kill interest instead of nurturing it.

The very best environments will have other kids who are engaged. It is induction into a culture, with its own language, ways of thinking and values. If you can't find that directly, you have to do your best to create a mini version as a family.

You can turn almost anything into a little maths games, card or dice games provide an opportunity for probability puzzles, the environment provides things to estimate and count, you can challenge them on car trips with rates and distances, etc etc etc. How many sides does a circle have?