Maandelykse Mathematische Liefbebbery, Purmerende (1754-69)

You know the Facebook post is in English and from 2025, right? 😂

No, I am saying you are wrong

And textbooks, calculators, accountants, and @[email protected], who also explicitly pointed out that what you did was 10-(1+1). I see you didn’t read the textbook either then.

No one else

Nope, also all the other parties listed above, who all agree with me

The saddest, and funniest, part is that you are so egotistical that you don’t see why you are wrong

That would be you again, after it has been explained to you many times, by me, other commentators, and Maths textbooks.

Maybe you will get it one day, but I won’t be there for it

Again that applies to you only, the only one here who thinks 10-1+1=8 when doing addition first, even though 11-1=10.

Self reflection is good.

How do you know when you haven’t tried it yet? If you had, you would realise you also owe @[email protected] an apology too

I know it is wrong, which is why I am telling you what my mistake was originally

But failing to understand what your actual mistake was, coming up with -1+1=-2, and not -1+1=-0

The fact that you still don’t get it demonstrates your complete lack of understanding

That would be you, the one who thinks order matters, and that -1+1=-2, not -0.

Order does matter

Nope!

+10-1+1=10

+10+1-1=10

-1+10+1=10

+1+10-1=10

+1-1+10=10

-1+1+10=10

Put those all into a calculator, and/or ask an accountant about it.

that order is left to right.

And yet, going RIGHT TO LEFT +1-1+10=0+10=10, same answer… though I have no doubt you think it’s +1-1+10=+1-11=-10

The original equation is written correctly

and 10-(1+1) isn’t, hence your continued wrong answer

My mistake was doing the addition before the subtraction when the equation reads 10 - 1 + 1

No, your mistake was doing 10-(1+1) where the question reads 10-1+1, and not +10+1-1 <== this is addition first, you add all the positive numbers together first, then do the negative numbers This is literally the textbook way to do it

According to you 6a²b-11a²b+5a²b-7a²b+2a²b=6a²b-16a²b-9a²b=-19a²b, and yet the textbook quite clearly states it’s -5a²b, which is because it’s 6a²b+5a²b+2a²b-11a²b-7a²b=13a²b-18a²b, and NOT 6a²b-(11a²b+5a²b)-(7a²b+2a²b)

10-(1+1)=10-1-1 which is what you did, which is not 10-1+1. You “added” 1 to -1, and got -2 instead of 0

How are you still not getting this?

It’s not me who’s not getting it.

No it wasn’t.

Yes it was. Read the textbooks.

The original equation is written correctly but the logic is incorrect

No your logic is incorrect. You’re incorrectly adding brackets to it.

in order to make it work the way I declared you have to do the equation x - y + z doing the y + z first

By putting it in brackets which is not how addition is done first. Doing addition first for x - y + z is x + z - y, not x - (y + z)

which was the mistake doing addition then subtraction

No, the mistake was you put the addition in brackets, -(1+1)=-2, not -1+1=+1-1=0. As per the textbook, the sum of any 2 numbers can only have 1 value. That 1 value for -1 and +1 is 0. -1+1=0, +1-1=0, not -1+1=-2

doing addition then subtraction instead of addition and subtraction in order from left to right

The rules are you either do addition then subtraction, OR you do left to right. There is no such thing as addition then subtraction left to right.

Addition then subtraction 10+1-1=11-1=10

Left to right 10-1+1=9+1=10

What you did 10-(1+1)=10-2=8

I see you are still being a bad teacher

says bad student, who didn’t try what the teacher said to try

who refuses to listen

that would be you again. You didn’t try it on a calculator, you didn’t ask an accountant. You didn’t even read and understand my examples. Read the textbook - it’s not just me telling you this.

I am not continuing with you

Because you’re unwilling to admit you’re wrong and refuse to try what the teacher and textbook have told you to do, and also refuse to ask an accountant about it

The fact that you still don’t get it demonstrates bad faith

Nope, that’s you again. You’re even arguing with literal textbook examples.

willful ignorance, and an unwarranted superiority complex

Also you, thinking you’re above Maths teachers, calculators, accountants, and Maths textbooks. According to you all of us are wrong, and only you are right. Get a grip

10-1+1=10 only if you don’t the addition first 1 + 1 = 2 - 10 = 8

Nope, yet again you just did 10-(1+1), which is wrong for 10+1-1. It gives 10 in any order. 10+1-1=11-1=10 <== did addition first, got 10. Accountants would have a nightmare if order mattered. “Did we receive this payment first, or this invoice? The order matters! ARGH!”

which was my mistake, which I already stated.

No, your mistake was adding brackets, 10-(1+1) ISN’T how to do addition first. 10+1-1 is. Ask an accountant! 😂 As you discovered 10-(1+1)=10-1-1, which isn’t 10+1-1, nor 10-1+1. 10-1-1=8, which is what you did - 10-1-1=10-(1+1) - 10-1+1=10, 10+1-1=10.

I see you still didn’t try it on a calculator yet then

Enjoy the egg on your face bud

None on my face. My students do very well in their tests. How about you? BTW try it on a calculator and guess what answer you’ll get. hint: it’ll be the same answer regardless of which order you do it 😂

To save you some trouble, here’s the results from my calculator…

10+1-1=10

10-1+1=10

-1+10+1=10

+1+10-1=10

-1+1+10=10

1-1+10=10

I feel bad for your students if you cannot see why you are wrong here

My students know I’m right. Everyone’s students know that’s right. It’s only adults who’ve forgotten the rules who get this wrong.

I am not going to argue with you about it

Nor should you. I’m a Maths teacher.

This was resolved almost a month ago

And yet you still don’t understand what’s wrong with what you said.

Read the original equation again, plug some numbers into it, and try again.

That’s what you need to do. You’re the one coming up with wrong answers when you change the order. Changing the order doesn’t change the answer.

If you still don’t get it I cannot help you

It’s not me who doesn’t get it. I teach it.

The brackets are used to make the equation look cleaner

No, they’re used to show deviations from the usual order of operations. If I want 2+3x4 to equal 20, then I have to write (2+3)x4.

10 - 1 + 1 = 8 doing the addition first

No it isn’t. 10+1-1=11-1=10 is doing the addition first. Note same answer. You in fact did 10-(1+1) - you added brackets which changed the answer, thus a wrong answer

10 - 1 - 1 = 8 regardless of order because it is all subtraction

Not all of it. You’re forgetting the 10 is really +10. -10-1-1 would be all subtraction. +10-1-1 is addition and subtraction.

it is not the same regardless of order

Yes it is! 😂 It is always the same regardless of order, as I have just shown you, again.

10-1+1=9+1=10

10+1-1=11-1=10

-1+1+10=0+10=10

1-1+10=0+10=10

1+10-1=11-1=10

-1+10+1=9+1=10

you do it left to right making it incorrect to do 1-1 first.

It’s NOT incorrect to do 10-1+1 or 10+1-1. It IS incorrect to do 10-(1+1), which is what you did

By doing it out of order and incorrectly I was able to make my statement true

It was solely because you did it incorrectly. Order doesn’t change anything.

÷ could be a minus sign

No it couldn’t.

https://en.wikipedia.org/wiki/Division_sign?wprov=sfla1

Did you check the reference? It says % can be used as a minus sign, not the obelus. Welcome to what happens when you’re next-door neighbour Joe Blow can edit Wikipedia.

The issue normally with these “trick” questions

There’s no “trick” - it’s a straight-out test of Maths knowledge.

the ambiguous nature of that division sign

Nothing ambiguous about it. The Term on the left divided by the Term on the right.

A common mistake is to think division is prioritised above multiplication

It’s not a mistake. You can do them in any order you want.

when it actually has the same priority

Which means you can do them in any order

did addition before subtraction instead of left to right

No, what you actually did was put it inside brackets, thus changing the number of terms. Doing addition first gives the exact same answer as doing subtraction first…

subtraction first 10-1+1=9+1=10

addition first 10+1-1=11-1=10

You did 10-(1+1), hence the wrong answer. It doesn’t matter which order you do it, though often students make mistakes with signs when they change the order, which is why we teach to do left to right.

Mathematics isn’t some objective truth

Yes it is. That’s why it’s such a huge part of Physics.

it’s just human made structures

The notation is. The rest is underlying laws of Nature.

Sometimes we can even apply them to real world situations!

Maths whole reason for being is to model real world situations.