your "times tables"? You know "once two is two, two twos are four..." and so on.
You sat in the classroom and just about shouted them out. You had to learn them by rote - all the way from the "one times" to the "twelve times". They formed part of "mental" (mental arithmetic) tests and you had to use them in "multiplication" and "long division" problems as well as "simple interest" and "compound interest".
Er, yes I did maths the old fashioned way. By the time I reached teacher training college there was something called "new math" with "set theory" and other theories that none of us pretended to understand.
When I went teaching I insisted that times tables had to be part of the maths as well. If I flung a "seven eights" at a child I expected an almost instant answer. The other members of staff criticised me for this. The school inspector thought it was a "good idea" and the parents said things like, "At last he's learning his times tables."
At the beginning of the year the children couldn't see the point. By the end of the year they could. Their maths was much improved. Some of them were teaching their younger siblings.
The following year I moved out of the classroom into the school library. (In those heady days schools actually had libraries and dedicated librarians.) I kept the library open at lunch times. It would always be crowded. I kept games there - chess, Scrabble, Go and other standard board games. I made other "times-table" games as well. They were always in use.
My parents insisted we know ours - my mother would ask us when we were least expecting it. I can remember holding my fingers up at the meal table so as not to answer with my mouthful and accidentally getting soap in my mouth answering when getting my hair washed. If we got it wrong then precious free time would be spent getting it right. My nephews were taught theirs in the same rigorous fashion by my mother.
I am not a mathematician. I am not particularly interested in maths. I had to do statistics at university and I even helped tutor some students but I didn't care for it. Despite that I could "add up" and "take away", "multiply" and "divide".
I can still do it. It happens to be very useful. I don't need a calculator.