The 'difference' between an Angiosperm and a Gymnosperm is that Angiosperms are flowering plants while Gymnosperms are not.
A woody vascular plant in which the ovules are carried naked on the scales of a cone, e.g. a conifer, cycad, or ginkgo is called 'gymnosperm'.
A plant in which the sex organs are within flowers and the seeds are in a fruit is called 'angiosperms'.
So, whats common? They both have seeds! Sperm = seed. Its in the name people!
Well they have seeds in common. Gymnosperms are plants that produce only seeds while angiosperms are plants that produces flowers and fruits.