Factor - notes are allowed in certain literature exams but by no means all.
Teaching times-tables fell foul of educational fashion iin the 1970's - it was deemed far too fascist to make kids memorize things by rote. Consequently a generation of adults can't multiply quickly and easily.
It was at the other extreme when I was a child - while our teacher did all her admin we had to chant our times tables up to 12 times table, then units of length, weights, and measures.
'four gills one pint, two pints one quart, four quarts one gallon........12 inches one foot, three feet one yard, 1760 yards one mile, 22yards one chain, ten chains one furlong, 8 furlongs one mile'
proper brainwashing and I can't forget a bit of it, but the problem is I still remember as well the teacher's car number plate - YRJ 308 - because it all sort of got caught up into the same mental template, some of which is useful, but to be honest I've never measured a chain of anything, ever in my life.
Or calculated the cosine of a single angle.