You are kind of mixed up, there. The US voting system does not record fractional votes, so you reasoning is specious. If you had 999 voters and 500 of them voted for Festus, that would be 50.05%, which is both a slim majority and 50% + 1. The meaning of “50% + 1” is not 51% but a single vote more than 50%.
What does 50% of 99 votes mean to you?
What it means is one vote more than half. We’re talking numbers, not percentages. Half of 99 votes is 49.5, but you can’t have half a vote, so it boils down to 49 votes. One more vote that 49 is 50. If you get to 50 in the scenario, the other candidate can only get 49.
Note that in the US, you usually don’t need a majority to win the election; you need a plurality: more votes than anyone else (there are some races, like the George senate race, that are exceptions). If there are more than two candidates, you can win by getting more votes than anyone else.
Could be much less than that, even, with (almost) no lower bound above zero. It depends on turnout in the various states: If, hypothetically, turnout were so low in each of the low-population states that only one person voted in each of them, while all of the high-population states had 100% turnout, then you could win with a total that rounds to zero at any reasonable number of decimal places.

You are kind of mixed up, there. The US voting system does not record fractional votes, so you reasoning is specious. If you had 999 voters and 500 of them voted for Festus, that would be 50.05%, which is both a slim majority and 50% + 1. The meaning of “50% + 1” is not 51% but a single vote more than 50%.
Which again by the math is not correct. Let me ask you this: what is a majority of 99? According to you it is 49.5+1 = 50.5 => 51 rounded up since you do not count fractional votes. Thus by your definition 50 is NOT a majority of 99.

What it means is one vote more than half. We’re talking numbers, not percentages. Half of 99 votes is 49.5, but you can’t have half a vote, so it boils down to 49 votes. One more vote that 49 is 50. If you get to 50 in the scenario, the other candidate can only get 49.
But that’s NOT the math you are claiming. You don’t round until the end otherwise that’s not 50%+1. (0.5 x 99) + 1 = 49.5 + 1 = 50.5 which you THEN round up.
Why get fancy (and wrong) with the 50%+1. The definition of majority is “more than half”.

Why get fancy (and wrong) with the 50%+1. The definition of majority is “more than half”.
Be cause 50%+1 makes it much clearer what a small margin of voters is being referred to, whereas “a majority” doesn’t bring up the same image. Your nitpick, on the other hand, is little more than annoying.

Be cause 50%+1 makes it much clearer what a small margin of voters is being referred to, whereas “a majority” doesn’t bring up the same image.
But mathematically incorrect in half the cases. Why not say “more than half”? Anyone can picture that AND it is the correct definition of “majority”.

Your nitpick, on the other hand, is little more than annoying.
But it is correct.
In keeping with fighting ignorance (since I hear the 50%+1 a lot)
The expression “at least 50% +1” is often misused when “majority” is actually intended.[1]: 4 However, this is incorrect when the total number referred to is odd. For example, say a board has 7 members. “Majority” means “at least 4” in this case (more than half of 7, which is 3.5). But 50% + 1 is 4.5, and since a number of people can only be integer, “at least 50% + 1” would mean “at least 5”. An example of the expression’s misuse to refer to a majority is the 50+1 rule.
Wikipedia
Definition: When a group needs to make a decision, a majority vote is often used. This means that more than half of the group needs to agree on something for it to happen. “50 percent plus one” is a way to estimate what that number is. For example, if there are 100 people in the group, then 50 percent plus one would be 51 people. However, if there are an odd number of people in the group, this estimate might not be exact. So, it’s better to just say “a simple majority” which means more than half of the group needs to agree.
LSDLaw

But mathematically incorrect in half the cases. Why not say “more than half”?
Because it doesn’t bring up the same image of the barest majority possible, the way 50%+1 does. Didn’t I just state that?

Because it doesn’t bring up the same image of the barest majority possible, the way 50%+1 does. Didn’t I just state that?
But it is wrong for an odd number of voters. Didn’t I just state that? In that case it is not the barest majority. It is 0.5 votes => 1 vote higher than a majority. So a person should not use it as the definition of a majority.
ETA: Are you claiming that for 99 voters that 51 votes is the barest majority and 50 votes in not a majority because that’s what your math says.
It’s clear that you’re technically correct, but you’re not addressing my point at all.
TIL, During WWII the US Army created a military designation called “Playwrite” for a unit responsible for making training films. Only nine soldiers were given that designation and four of them were Frank Capra, William Saroyan, Stan Lee, and Dr. Seuss.

It’s clear that you’re technically correct,
Thank you.

but you’re not addressing my point at all.
I did. IMO, more than half is just as visual as your definition. I would even argue moreso for lower numbers but even small children can visualize that this part is bigger than that part for a general case. Imagine a picture. On one side is 4 rows of 10 then a bottom row of 9. The other side has 5 rows of 10. That is easy to see which side has more.
Or I say 49 voted Harris, 50 voted Trump. Are people going to be confused who won thinking, “No wait! That’s only 50% + 0.5.”

Definition: When a group needs to make a decision, a majority vote is often used.
On the other hand, when a group needs to make a decision that the minority will bitterly dislike, to the point of rebelling against the vote and the authority of the group, it takes a 2-1 or 3-1 supermajority to make it stick. The US Civil War was one example. The supermajority necessary to pass a constitutional amendment is another.
Can y’all take this elsewhere? The reality is that if the vote were that close, there would at least be recounts.

During WWII the US Army created a military designation called “Playwrite” for a unit responsible for making training films.
Did the Army misspell Playwright, or did you?
Alas, that was me.

It’s clear that you’re technically correct
Which, as we know, is the best kind of correct. But unlike the “playwright” thing, this whole topic is not remotely “interesting”.
I was thinking about classic movies this morning, and Carl Dreyer’s staggering masterpiece The Passion of Joan of Arc came to mind as a longtime favorite. Then it occurred to me, I don’t know why Joan of Arc is called “Joan of Arc,” or “Jeanne d’Arc” in French (where d’ is an abbreviation of “de” meaning “of”). What or where is this “Arc” that Joan’s name is apparently marking as her origin?
So, for the first time ever, I looked it up, thinking there would be an easy answer, and an inconsequential but nice bit of trivia to file away.
However, as it turns out, it’s actually a bit of a historical mystery. And not only does nobody really know for sure how the name came about, but there’s a plausible (if unprovable) hypothesis that her surname, after her father’s family name, was actually “Darc” (with a typically squishy range of alternative medieval spellings reflecting an approximate pronunciation) and the whole d’ business is an accidental back-formation arising many years later out of confusing inconsistencies in how French and Latin were written at the time.
Which makes this a really good piece of trivia.

Which makes this a really good piece of trivia.
You mean she wasn’t Noah’s wife?
Actually, I congratulate you – an excellent point that I’ve never seen anyone address before.
Thanks. Open-minded curiosity is a powerful, powerful thing.