Monday, August 13, 2012

Some Serious Math!

Okay, this was the most fun I have had in a while. I had a different blog planned for today but I just had to interject this one. Kayla sent the following questions that all involve some serious mathematical calculations.

Kayla's 1st and 2nd questions:
“Do you and your ninth cousin 2 times removed share anything, or even related? ...also found this same person through another side of my family tree listed as 8th cousin 10x removed. Any relation at all?”

Yes, if you are truly 9th cousins twice removed you do share a common ancestor. 9th cousins share a 8th great-grandparent. The twice removed simply means that the 9th cousin and the grandchild of a 9th cousin are being compared. So the common ancestor would be the 9th cousin’s 8th great-grandparent and the twice removed’s 10th great-grandparent (same person).

Okay, now the 8th cousin 10 times removed. The 8th cousins would have a 7th great-grandparent in common. The 10th removed would be the 8th great-grandchild of one of the the 8th cousins. So, their common ancestor would be the 8th cousin’s 7th great-grandparent and the 10th removed’s 17th great-grandparent (same person).

Kayla's 3rd question:
“Are you related to your 7th cousin 3x removed? I just have heard it's so distant, but nevertheless you share a set of distant great grandparents...”

This is the same principle. 7th cousins share a common ancestor of the 6th great-grandparent. 3 times removed means it is the 7th cousin and the great–grandchild of a 7th cousin being compared. The common ancestor would be the 7th cousin’s 6th great-grandparent and the 3 times removed’s 10th great-grandparent (same person).

Kayla's 4th question:
“I recently found out two cool facts. Loretta Lynn (through her mother Clara Ramey) happens to be my third cousin 1x removed. How much of a relation is there here?”

3rd cousins share a common ancestor of the 2nd great-grandparent. Once removed means a 3rd cousin and the child of a 3rd cousin are bring compared. So the common ancestor will be the 3rd cousin’s 2nd great-grandparent and the once removed’s 3rd great-grandparent (same person). That isn’t that big of a relationship difference in the grand scheme of things, certainly a lot closer than your first two examples.

Kayla's 5th question:
“Last question, I also found out that my 12th great grandmother (long shot, I know! lol) happens to be Rebecca Rolfe (aka Pocahantas). Is that even related? I know it's a direct bloodline, but being so distant, does that make me Indian AT ALL?”

Wowser! You really want to test my math skills don’t you! IF Rebecca is your 12th great-grandmother and IF she is the only person in your entire ancestral line that is an Indian, then you would be 1/16384th Indian. The number doubles with each generation. If your dad is 100% Indian that makes you 1/2 Indian. If your grandfather is 100% Indian it makes your dad 1/2 Indian and you 1/4 Indian. If your great-grandfather is 100% Indian that makes your grandfather 1/2 Indian, your father 1/4 Indian and you 1/8 Indian. If you continue this all the way to the 12th great-grandmother then the number goes to 1/16384th. Who knew that math skills would actually come in handy!

Copyright © 2012 Michele Simmons Lewis


  1. My wife and I have the same 9th gr-grandparents. Her 8th gr-parent is the oldest of their 11 children, while my 8th gr-great grandparent is his younger brother , 10th of 11. How are my wife and I related, besides marriage ?
    Thanks for the help...Gary G

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  3. Replies
    1. Thanks Michelle, that's what I thought, but wasn't sure :-)

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  4. I get "math" type questions quite often and they usually make my brain hurt :) Legacy Family Tree (the database program that I use) automatically calculates the relationships for you. I am sure the other major programs do the same thing. It makes it soooooo much easier :)