Many a time on our local market stall, they would use a scrap of paper to add up 2 items and Im stood there with the right money in my hand waiting for them. I dont think many people can add or subtract without a calculator these days, young or old. Im not brainy but I can at least do the basic things (and more if I put my mind to it) which is half the problem, some dont want to have to use their brains. I think keeping those little grey cells working as long as possible is the best thing