What are the differences between UK and US education systems?
For example, the grades/years are different and so on.
The two biggest differences are early specialization and the Grade Point Average (GPA) system vs a series of exams (SATs, GCSEs, A-Levels, university finals).
The GPA system encourages constant assessment over the details. It is common for a student's grade to depend on reading responses, quizzes, daily homework, presentations, classroom participation, and so forth.
The UK system is more of a series of exams. It is very possible, especially at the early level, for bright children who are lazy to succeed. While there are multiple inputs to the assessment of a US student as described, in the UK there is generally only a couple of inputs in the form of a final exam, weighted at 100%. The concept of being graded in a manner that will affect your university applications on participation, presentations, or homework is simply not there in the UK.
The other major difference is early specialization. For a start, school starts one year earlier in Britain. Many British students start moving toward a certain discipline at a very young age. At 16 years old following GCSE's students will move towards three or four core subjects for A-Levels, and then go on to study one of these subjects at university level. Switching subjects at bachelor's level involves restarting college. There are no general education requirements.
This stands in stark contrast with the US system where it is not until second or sophomore year of your bachelor's that most begin to specialize in a certain subject. In the US, everyone is expected to do a wide range of subjects up to an A-Level equivalent standard by the time they graduate.