KS1 is the two years of schooling in maintained schools in England and Wales normally known as Year 1 and Year 2, when pupils are aged between 5 and 7 years.
Topics covered within KS1 include:
Addition, subtraction, division and multiplication, doubling and halving, simple mental maths, shape and space, times tables, measuring and weighing, using money & telling the time.
At the end of KS1, students sit SATs exams which are marked by teachers within the school.