Skip Navigation

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱

@ SmartmanApps @programming.dev

Posts
26
Comments
418
Joined
3 yr. ago

  • Maths

    Jump

  • 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

  • Maths

    Jump

  • 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.

  • Maths

    Jump

  • 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.

  • Maths

    Jump

  • 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.

  • Maths

    Jump

  • 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 😂

  • Maths

    Jump

  • 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)! 😂

  • Maths

    Jump

  • 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!

  • Maths

    Jump

  • 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?

  • Maths

    Jump

  • 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 :-)

  • Maths

    Jump

  • 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.

  • Maths

    Jump

  • 6/100 * 50 = 50/100 * 6

    =6x5 /10 (2 zeroes cancel out)

  • Maths

    Jump

  • 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.

  • Maths

    Jump

  • 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.

  • Deleted

    Permanently Deleted

    Jump

  • That is why the narrow application of standards is another obstacle to learning

    No it isn't

    I was top of my math classes...

    Survivorship bias

  • Deleted

    Permanently Deleted

    Jump

  • i can figure out anything on the 12x12 timestable in a few seconds

    Within 2 seconds is the standard expected. Longer than that is lagging behind your peers

  • Deleted

    Permanently Deleted

    Jump

  • As a teacher, no, memorization is an important step before understanding

    Yep, same. Without fail the kids I run into who are bad at Maths and "hate Maths" have been poor at mental arithmetic. i.e. not keeping up with what is being taught because they're still struggling with the number-crunching. Once they get up to speed with mental arithmetic their marks improve and they don't hate Maths anymore.

  • Deleted

    Permanently Deleted

    Jump
  • Deleted

    Permanently Deleted

    Jump

  • so why even bother with memorizing if I can calculate it fast enough

    The standard is to be able to answer a times table question in 2 seconds, so if it's taking longer than 2 seconds to calculate it then it's not fast enough.

  • Deleted

    Permanently Deleted

    Jump

  • 7 x 8? It’s 7 x 10 - 2 x7. 12 x 11? It’s 12 x 10 + 12

    Welcome to getting less questions done in a Maths test, and thus less marks, cos it's taking you longer than the rest of the class to do the number-crunching parts