New land found in Will

I was looking through all of the will paperwork and found that there is another plot of land untouched that is also showing mineral rights go to myself.

I am trying to figure out what this means as it says the following.

1/2 interest in 8/80ths undivided interest in oil, gas and other minerals in the following described property:

it covers a full section (Half of one and half of another) But unsure on what it means by in 8/80ths. Anyone able to help?

8/80 = 10%

You own 1/2 of 10% of the tract.

Otherwise, could be a typo if there is a reference to 8/8ths in other portions of the conveyancing document. But, that's a hard one to prove. 8/80ths is unusual though. Who was the Grantor and how much did they own originally?

8/8ths is standard parlance for 100%, I have never seen any instrument refer to 8/80ths unless there was a specific reason that ownership would be split 80 ways.

It was my Great Great Uncle who left it to my grandmother who left it to my mom. The paper is very old but does say 8/80ths. not sure if it was a typo or not. Any way to verify ownership of royalties?

Could be referring to an eight-acre mineral interest out of an eighty-acre tract. Somebody owned 80 mineral acres (half of a quarter section) and decided to give eight acres of that to A, twelve acres to B, twenty acres to C, and forty acres to D. So A would own an 8/80ths MI in the 80-acre tract, B would own a 12/80ths MI, C would own a 20/80ths MI, and D would own a 40/80ths MI. Just a different way of saying 10%, 15%, 25%, and 50%.