The another child may just sit up, then
The sequence of development defines the general order that a child develops, but every child is different and therefore this can vary consistently.
For example, one child may lose the first tooth at 5 years old and another child may lose it at 8. Another example could be that one new born baby starts rolling over, later sitting up, then start walking after crawling, but another child may just sit up, then crawl and later start walking, missing one element without compromising the expected pattern.The rate of development is instead the speed of which a child develops and again this can vary in each child. For example, one child may start walking unaided before their first birthday, but another child may not start walking unaided until after their first birthday. Every child will learn to lift the head up, but some of them will learn to do this earlier than others. It’s important to know the difference between the sequence and the rate of development because it helps to identify and meet the children’s individual needs.
For instance, as it is expected a certain sequence and rate of development, it helps the early years practitioners to recognise if a child has some special educational needs and it helps planning the activities in order to make sure that also SEN children get enough support in the class.