* First cousins have the same set of grandparents
* Second cousins have the same great-grandparents
* Third cousins have the same great-great-grandparents
The quick method of remembering this is count the number of ‘greats’ and add one to get the degree of cousinship.
Removed cousins involve people who are not of the same generation. So you need to go ‘up’ the generation line on the family tree of the person who is from the younger generation., and then determine the relationship, as though they had been of the same generation. So a first cousin once removed would have great-grandparents who are the grandparents of the older relative.
Cousinship can only be ‘removed’ upwards.