Key Stage 1 covers ages 5-7 and years 1 and 2 at school.
During this time, your child will have a number of subjects and skills to focus on, before taking part in their first national curriculum tests at the end of Key Stage 1 called SATs. These are not pass/fail tests but simply provide an indication of your child’s progress, allowing teachers to plan future learning. Social and cognitive skills such as improving attention space and sharing with peers will play a part in education at this stage as well as academic subjects.
Source Reference: What are the Key Stages in the National Curriculum? - From WHSmith