Not knocking all teachers, but there have been a few situations I have come across, one was very much like the above, probably the worst was my youngest daughter was struggling with her maths, not that I'm that good but she came home with about 10 old GCSE type exams, the teacher had downloaded some old papers as a test for the class, there are a couple of questions that came to mind that I thought were now out of context due to the reduction of imperial measurements, I was a little surprised that these were still part of core maths, yes perhaps learn them but not in exams.
The first was a question where the old measurements i.e. inches, feet, yard, chain, furlong & mile, the question stated how many inches in a foot, feet in a yard, yards in a furlong, furlongs in a mile etc. the actual question then was how many yards in a mile, she had no idea what most of those measurements were so I showed her that if there are 8 furlongs in a mile, 220 yards in a mile then there are 1,760 yards in a mile simple to me as I already knew the answer, but for a 14 year old perhaps a bit of a task, there was another giving a plan diagram of the front of a house, the roof had 45 Deg angles on the ends these all had measurements, the question was to find the area of the plan view,she was ok with the rectangles, but got stumped on the sloping roof, I showed her that effectively without any complicated maths just imagine them as a square (hence the 45 angle) then divide the area by 2, simple, I was amazed that the teacher marked them both wrong? When I challenged them at a parents evening the teacher was adamant they were wrong & even stated that they knew a mile was 1220 yards ? I also had the experience of taking a teachers onto site (my boss was chairman of the Parents/teachers at a school), the idea was to show them what goes on in industry, well I will not go on but those trips put me off teachers.