Youtube comments of Beth Hentges (@bethhentges).
-
712
-
Thank you very much for this. I am from the USA.
My father fought in Germany, and his ancestors (only 1-2 generations earlier) were from Prussia, Bohemia, Bayern, and Luxembourg. In fact, my dad’s uncle fought in WW I, in Germany, also. After that war ended he went to Luxembourg to meet his first cousins.
I hope to travel to Europe some day. I had hoped to take my dad, but by the time I maybe could afford it, he was too elderly. He died in 2009.
One interesting thing. I was with my dad when he had an appointment with a doctor he hadn’t seen before. The doctor came in, greeted us, introduced himself. Then he said, “Hentges. That’s a German name, right? Have you ever been there?”
My dad said, “Well no, not as a tourist. I was there during the war.”
The doctor said, “Me, too, but I was on the other side.”
Then they each shrugged their shoulders and nodded their heads once as if to say, “I understand. War is hell. Been there. Done that.”
72
-
33
-
30
-
29
-
16
-
15
-
14
-
13
-
13
-
12
-
11
-
10
-
10
-
9
-
9
-
8
-
7
-
7
-
7
-
7
-
6
-
6
-
6
-
6
-
6
-
6
-
6
-
6
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
5
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
4
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
Yep.
I was driving home from college in 1980 or 1981 for spring break on the Saturday of the boys basketball state tournament.
Left St. Cloud in the evening, after performing in a concert, maybe 8:30PM-9:00PM. Just as I thought to myself that I was almost home—only another 40 miles left of a normally 3 hour trip that was already maybe 4-5 hours I fishtailed into the ditch in the median about 50 miles south of Minneapolis.
Too deep to have a chance of getting the car out without a tow. Walked up to the road to flag cars for help. One or two passed me by, but the next stopped. As a small, 20 year-old female, in the dark, in what was now a blizzard, I was relieved to recognize the driver as a gym teacher from my hs. You see there was actually lots of traffic for a blizzard because so many folks were heading home from the tournament.
During the next, very slow, 2-hour drive for those last 40-50 miles home, we picked up 3-4 other folks whose car was no longer on the road.
Thanks to the careful driving of the teacher we all made it home.
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
For some reason in the USA, in K-12 ed, and the first two years of college, we make a distinction between natural numbers (positive integers) and whole numbers (non-negative integers).
Then once you are in your third yr at college and start group theory/abstract algebra, then we change the definition of natural number to include zero.
In the USA, the number written
-3 is “negative three,” NOT “minus three.” The word “minus” should be used only for the operation of subtraction. In everyday life, we often hear “minus” used incorrectly as “negative.”
Also, in the USA -3 is an integer, but it’s not a whole number, because the whole numbers are the non-negative integers only.
I tell my students that definitions develop over time. They start as a general description, and they get more precise as the object becomes more understood. Along the way, “edge cases” are sometimes included and other times not. It’s important to know what those edge cases are so that when you engage with a new person/course/text, you will know you need to agree as to whether or not the definition is inclusive of the edge case or not.
For the purpose of the new discussion we need to know:
Is zero a natural number?
Can a line be parallel to itself?
Is a rectangle a trapezoid?
When we say suppose a and b are two ___ , are we allowing them to be the same ___ , or are we assuming they are distinct?
Regardless of which choice we make, we need to keep that in mind as we go forward in the statements of new theorems and definitions.
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
In English a “lie” is a false statement.
2^3=8
is a statement that is
true (always in R),
correct, and
right.
It’s an identity.
(It’s not a very interesting identity.)
2^3=6
is statement that is
never true.
It’s false,
incorrect, and
wrong.
It’s a contradiction.
We KNOW 2^3=8.
It SAYS 2^3 is the same as 6,
but we KNOW
2^3 is NOT 6. Hence the contradiction.
If I say to you, “the third power of two is eight,” then what I said is true and I have told you the truth about 2^3.
If I say to you, “the third power of two is six,” then what I have said is false, and I have told you a lie about 2^3.
The equation
x+3=2+x+1
is always true. It’s an identity.
The equation
x+3=2+x
is never true.
It’s always false.
It’s a contradiction.
The equation
x+3=2
is true for some value(s) of x,
and
is not true for other values of x.
Some say it’s “open.”
Most say it’s “conditional.”
There are some condition(s), some value(s) for x, for which it would be true,
and
there are other condition(s), other values for x for which it would not be true.
In mathematics,
right vs. wrong,
right means correct;
wrong means not correct.
In other uses,
right can mean the correct or the ethical thing to do;
wrong means the incorrect or the unethical thing to do.
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1