I remember back in the 1970's when I did Domestic Science as it was called then, when decimalisation happened all the weighing scales, measuring jugs and measuring spoons were replaced by ones in grammes and millilitres, also the recipe texts. It was a steep learning curve, but we all managed it. The teacher said that 100g was roughly 4oz as a guide.
We used to weigh our own ingredients, brought from home at school in the lesson. We could weigh out at home, but that brought its own problems, i.e. when making pastry there was then no extra for the rolling out! I think that the odd failure can be beneficial, provided the ingredients weren't extortionately expensive. You do learn by your mistakes.
I also had a wicker basket! You learn very quickly that decanting stuff like fresh fruit salad into a plastic freezer box is a less messy way to transport it home! Make use of plastic carriers without holes in to put casserole dish in, and so on.
I was lucky in that I enjoyed cooking. I wholeheartedly support teaching cooking in schools, I think it is as essential as Maths, English and Science. So much more than just cooking is learned, budgeting the cost of ingredients, nutrition, use of leftovers, food hygiene, increasing/decreasing quantities for different numbers of people and so on.