South Africa was a British colony until 1961, so the imperial system of measurement was standard. When the country achieved independence, the metric system was adopted. We also changed from the South African pound to South African rands.
This meant that for a long time after I started school, we used to convert from one to the other – both currency and measurements. Partly because some text books were pre-1961, partly because shops often displayed both, partly because my parents always did it.
After the internet revolutionised the world, this skill has proved invaluable to me. I can figure out recipes, online product specifications, weight conversions, sizes etc pretty quickly without using a converter.
In the 1970s the local politicians decided it would be a good idea to push the metric system. They put up road signs with dual imperial/metric measurements. This was an immediate flop! People disliked this so much that the signs started getting vandalized. People would paint over the metric portion of the sign. I remember one sign with the word NO painted over it. Some signs simply disappeared in the.middle of the night. The fools in power realized their error and had all the signs removed.