I think it’s good to have a good set of these tables memorized and then based off those you can bounce your tricks. Eg if you know 5x12 by heart, you get 5x24 by intuition. Or even if you know 24/2 for that matter. I use simple examples but this could scale to less memorable numbers too.
It’s really helpful for quadratic factoring, too, since knowing at a glance that –56 is ±7 × ±8 keeps your working memory free to actually focus on the mathematical skills/concepts/problem.
I think it’s good to have a good set of these tables memorized and then based off those you can bounce your tricks. Eg if you know 5x12 by heart, you get 5x24 by intuition. Or even if you know 24/2 for that matter. I use simple examples but this could scale to less memorable numbers too.
x5 has its own trick, for me it’s ÷2x10 (or x10÷2, whichever feels more intuitive) so 5x24 => 24/2 => 12x10 = 120
It’s really helpful for quadratic factoring, too, since knowing at a glance that –56 is ±7 × ±8 keeps your working memory free to actually focus on the mathematical skills/concepts/problem.