💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱

For quick and dirty I’d probably just go with 3738 = 4040 -> 16% which is kinda close to 14% eh?

Quick and dirty and accurate is 38=40-2. So 38x37=(40-2)x37=40x37-2x37=1480-74=1406

I don’t think “two-dimensional number system” is something you’d hear mathematicians say

I teach Maths and would’ve thought that was referring to the Cartesian plane.

I’m gonna track down all my HS math teachers and punch each and every one of them in the mouth.

Understandable if you’re in the U.S., where Maths teachers don’t have to have any Maths qualifications. Other places, where you do have to have Maths qualifications, we teach this.

Where accuracy is important, since we almost always have a calculator with us now, that’s a no-brainer.

Unfortunately most calculator apps were written by no-brainers who didn’t check they had their Maths correct. If you need accuracy then get a name brand like Sharp or Casio.

May as well just get out the calculator app to make sure

Calculator apps get order of operations questions wrong because of programmers who were too lazy to check they had their Maths correct

My point with those numbers is to just use a calculator.

My point is avoid calculator apps like the plague. Use name brands like Sharp or Casio.

Why 2nd guess anything?

Guess what the programmer of your calculator app did 😂

Wow, that’s nice! I like it

It’s called grouping. It’s part of the curriculum here. Break the arithmetic into easily calculated groups.

I just hope that you are not starting grading your students with the phrase “You’re absolutely right!”

I’m not in the U.S. no. We still require teachers to be qualified here (Masters)! 😂

There’s nothing wrong with calculators

There is if you’re talking about calculators on phones, etc. Almost all of them give wrong answers to order of operations questions because the programmer didn’t bother checking their Maths first. It’s so bad that the Windows calculator in Standard mode says 2+3x4=20. Stick to name brands like Sharp and Casio. They have money invested in the success of their products, so they take more care to make sure it’s correct!

Yes, 47% of 47 is certainly much easier to determine

And your real life example of a 47% discount on a $47 item is… where exactly?

Yeah, now calculate 6% of 36

6x3x10 + 6x6, move decimal point 2 places to the left

Replies itt make me believe that everyone on Lemmy is a chatbot

I’m a Maths teacher :-)

people forget that percent literally means per 100 or /100

Yes

the of is standing in for multiplication

No. The M is for Multiplication. O is for Order, as in “to the order of”, as in Exponents.

6/100 * 50 = 50/100 * 6

=6x5 /10 (2 zeroes cancel out)

I just think the symbol “%” algebraically means 0.01

Warm. It actually means “per 100”, hence the slash to represent a vinculum and the 2 zeroes. Of course in decimal that converts to 0.01.

Yeah stuff like that really ain’t it

Yes it is

It works in a few use cases,

It works in every case where you have multiplying and dividing, including fractions and percentages

but is objectively wrong

No it isn’t

detracts from understanding the topic properly

Enhances it actually

That’s why I teach percentages as the fractions they are.

Sounds like you’re only teaching as much as you understand. Try understanding more. Students love the tricks that make Maths easier, including this one.