Metric - I feel such a fool!

It’s relative weight that gets me. I know what 11stone or 12 is ?????but when’s it’s in kilos I have no idea if that is good, bad or appalling!

450g (give or take a bit!)

I've always just remembered 10cm = about 4 inches. I still don't know how much a pound of mince is.

It's approximate and a useful conversion (I use 10cms = 4") if you're thinking of depth of snow, rainfall etc, but if you need something more precise best to measure carefully .

I just devide by 10 and multiply by 4 , I don’t / can’t do metric

I just remember the rhymes from long ago!

‘ Two and a quarter pounds of jam, weighs about a kilogram’

and

‘ A litre of water’s a pint and three quarters’.

I always use the 30cm = 12".
near enough.

It is probably because the standard ruler measured 12 inches, and was replaced with one measuring 30 centimetres, almost the same size. Some rulers had inch/centimetre measurements on different sides.

Well, you are not far off, MamaCaz! It's 30.48cm, so not much in it. .

The one that I do remember exactly is one gallon= 4.456 litres.
I worked in NHS finance and the boiler house would order the hospital fuel in gallons and the oil company would deliver in litres and that was forty years ago.
It caused no end of problems.