As the saying goes, interest is the best teacher! Interesting mathematics, such as fast calculation, can be used to attract them to concentrate on mathematics: for example, in images, in examples, in various forms at the same time. Like, 99 times two digits can make him blurt it out,

38×99=3762

66×99=6534

Tell him: the difference between 3700 plus 38- 1 and 100-38 is 3762.

66- 1 = 65, 100-66 = 34 add up to 6534. ...

Like the top ten, like the top ten, the same quick calculation questions make children enjoy fast oral calculation.

When he is interested in mathematics, you can sit back and relax.