They would be the fourth cousins. They share a common 5 Great Grandparent.
They would be fourth cousins.
Your grandson and your sister's grandson are second cousins to each other.
You and your great uncle's grandson are second cousins.
You and your great great aunt's great grandson are third cousins.
Your grandchild through one daughter and your great grandchild through another daughter are second cousins, once removed.
they would be first cousins once removed. this is because the grandchild's parent would be your son's first cousin and because its the cousin's child, its once removed
You and your great aunt's grandson are second cousins. Your great aunt was the sibling of one of your grand parents, so your parent and your great aunt's child were first cousins. You and the grandson are members of the next generation and therefore second cousins.
Your grandson and your great great niece are second cousins, once removed, to each other
Your grandson and great grand son could be cousins,(first cousins once removed), they could be uncle and nephew, or they could be father and son. It depends on how they are related to your children. If your great grandson is the grandchild on one of your children and your grandson is the child of a different one of your children, they are first cousins, once removed. If your great grandson is the child of a sibling of your grandson, then they are uncle and nephew. But your great grandson could also be the son of your grandson. Then they are father and son
Your daughter and your uncle's great great grandson are second cousins, three times removed.
First cousins three times removed.
First cousins twice removed.
If your great great uncle (the brother of your great grandparent) had a great great granddaughter, you would be third cousins, once removed.