Sequencing is a very important skill for children to learn in preparation for reading. Sequencing usually involves a child being given a set of pictures. He may be told which is first in the sequence. He must then decide the order of the remaining pictures. He makes the decisions based on what he thinks the outcome will be from what happens in the previous picture.
Sequencing is also an important math skill. A child needs to learn how to sequence numbers properly in order to count. Sometimes a child is given a set of numbers in some unnamed pattern. The child must decide which numbers come next by deciphering the pattern. (Which is what you do in counting. You are actually adding one to the previous number.)