[MatueHarton]

It's vague for the reason that no exam questions are that confusing whilst being so simple. The actual maths involved isn't tricky. But if many people and some calculators get it wrong, then it's not laid out how it should be. I know it's very easy for us all to pretend we get it because it's the internet and we're all totally genius. I've done a lot of algebra and never have I had to apply a left to right rule in order to get the right answer. Could be the failing of my education but I don't think so.