This is a great toy/educational tool for quite a range of children. As a shape sorter it is great for kinds under one year old. For children around the age of three (my daughter's age) it is great for teaching them to recognise numbers and for older children it can be used to teach them about the time.
Already my daughter is putting the numbers in the right place but making sure they are the right way up (when you take a number out, it is still shown beneath the block that has been removed). She can recognise the numbers 1-4 so from 1 she can start counting around the clock face and learn what the other numbers look like.
She's still too young to understand about time (she just wants to push the two hands on the clock face together all the time) but I can see it being something she comes back to again and again.