MATH

[jm the mute]

anyone?

[gandydancer123]

uggh..not my thing..

[jm the mute]

[red lights]

masakit to sa ulo

[inigo]

Wait, paano ulit pwede maging hobby ang math? (serious inquiry, no sarcasm)

[inexperience]

As in math, nung HS i was good, pero nung college puro pasang wawa. 

[jm the mute]

Wait, paano ulit pwede maging hobby ang math? (serious inquiry, no sarcasm)

[Ralph_Petrucci]

Wait, paano ulit pwede maging hobby ang math? (serious inquiry, no sarcasm)

marami akong kilalang mahilig mag arithmetic just to pass time. ako mahilig din akong magcompute compute hahaha pero pagdating sa calculus tapos na ako. HAHAHAHA

i downloaded this app caled math trainer. saya lang. pabilisan to solve as many arithmetic questions hahaha

[jm the mute]

it keeps the mind sharp

[Poundcake]

I'm into math. I like to think of shortcuts to solve everyday math processes mentally. An example of the things I came up with is dividing any number by 5. My shortcut is to multiply that number by 2 then moving the decimal point one place to the left. Say you have 56.5, the answer is 113 with a decimal moved a place to the left, so 11.3

[jm the mute]

I'm into math. I like to think of shortcuts to solve everyday math processes mentally. An example of the things I came up with is dividing any number by 5. My shortcut is to multiply that number by 2 then moving the decimal point one place to the left. Say you have 56.5, the answer is 113 with a decimal moved a place to the left, so 11.3

nice tip

ang alam ko lang ung pag multiply ng any 2 digit number to 11...
ex: 23*11
2+3=5
put that 5 between 2 and 3. the answer is 253. bow

[dariusbabylon]

In. I just took Calculus refresher courses at coursera; and signed up for more.

[dariusbabylon]

I'm into math. I like to think of shortcuts to solve everyday math processes mentally. An example of the things I came up with is dividing any number by 5. My shortcut is to multiply that number by 2 then moving the decimal point one place to the left. Say you have 56.5, the answer is 113 with a decimal moved a place to the left, so 11.3

That's really multiplying by  (2/10). Or (1/5)

[Poundcake]

That's really multiplying by  (2/10). Or (1/5)

Yup, that's the point. It's easier to process it that way.

[dariusbabylon]

Yup, that's the point. It's easier to process it that way.

I'm just verifying the "short cuts".
And the x11 short cut of adding the digits of the two digit number - it's because of the fact that when you do long multiplication, both digits will have to be multiplied by 10, and will line up, thus, the need to add. But it's only valid  for two digits which add up to 9 max. If the sum is 10 or more, it doesn't work. It's because you have to "carry" the extra digit to the next left column when doing multiplication.

Eg 55x 11 is not equal to 5105, but 605

[Poundcake]

I'm just verifying the "short cuts".
And the x11 short cut of adding the digits of the two digit number - it's because of the fact that when you do long multiplication, both digits will have to be multiplied by 10, and will line up, thus, the need to add. But it's only valid  for two digits which add up to 9 max. If the sum is 10 or more, it doesn't work. It's because you have to "carry" the extra digit to the next left column when doing multiplication.

Eg 55x 11 is not equal to 5105, but 605

If the total of the two numbers exceeds 10, just carry over the tens digit of the sum of both numbers to the first digit (e.g. 87 x 11, 9 [first digit +1 due to 8+7 being more than 15, which is more than 10],5 [ones digit of the sum], 7 [second digit] = 957).

[dariusbabylon]

If the total of the two numbers exceeds 10, just carry over the tens digit of the sum of both numbers to the first digit (e.g. 87 x 11, 9 [first digit +1 due to 8+7 being more than 15, which is more than 10],5 [ones digit of the sum], 7 [second digit] = 957).

right, so it's not for all 2-digit numbers, as earlier claimed. If the sum of the digits exceed 9, there's an extra step.

Which makes it more complicated than just simply multiplying. Or using a calculator.

That's the real beauty of math, proving/ disproving theorems and finding (or trying to find) universal truths.

[Poundcake]

right, so it's not for all 2-digit numbers, as earlier claimed. If the sum of the digits exceed 9, there's an extra step.

Which makes it more complicated than just simply multiplying. Or using a calculator.

That's the real beauty of math, proving/ disproving theorems and finding (or trying to find) universal truths.

That extra step ain't difficult, actually. It even works for 3-digit numbers. And for what it's worth, solving basic arithmetic equations by using any mental math shortcut would be more than complicated compared to doing so by using a calculator.

[dariusbabylon]

That extra step ain't difficult, actually. It even works for 3-digit numbers. And for what it's worth, solving basic arithmetic equations by using any mental math shortcut would be more than complicated compared to doing so by using a calculator.

and multiplying any number by 11 (conventionally)  isn't difficult as well. Which is why I question the "short-cut" which needs an if-then-else statement.

[Poundcake]

and multiplying any number by 11 (conventionally)  isn't difficult as well. Which is why I question the "short-cut" which needs an if-then-else statement.

Other people don't have the mental computing power to easily deal with larger numbers and would rather work with smaller ones. Such shortcuts are not necessary anymore for practicing engineers such as myself and for other people who have a knack for numbers (presumably you), but for the benefit of everyone, these small tricks may help them mentally compute for stuff through easy-to-follow steps. Maybe you can share some of your math tricks as well so that you can actually contribute to this thread

[dariusbabylon]

Other people don't have the mental computing power to easily deal with larger numbers and would rather work with smaller ones. Such shortcuts are not necessary anymore for practicing engineers such as myself and for other people who have a knack for numbers (presumably you), but for the benefit of everyone, these small tricks may help them mentally compute for stuff through easy-to-follow steps. Maybe you can share some of your math tricks as well so that you can actually contribute to this thread

Point is, some "short-cuts" are not really shortcuts. In the x11 example, it's actually longer. You have to test the digits if they fall within a certain criterion. If yes, then do one thing. If not, do another thing (which consists of several iterations).

A "simpler shortcut" for x11 is multiply by 10 and add the same number. Thus 45 x 11 = 450+45 = 495. No if-then-else statement.

And just for argument's sake, people who have a "knack for numbers" may not be necessarily good in mathematics. They may be good in arithmetic, but not in the other branches of mathematics, which require logic and analysis.

Which brings me to your "contributing to this thread" statement. I've been "contributing to this thread" by verifying and analyzing the logic of the "math tricks". That is the essence of mathematics, after all.

[dariusbabylon]

Wait, paano ulit pwede maging hobby ang math? (serious inquiry, no sarcasm)

Several ways
Just for fun
https://www.edx.org/course/effective-thinking-through-mathematics-utaustinx-ut-9-01x

Use it for sports geekiness
https://www.edx.org/course/math-sports-notredamex-mat150x

[jm the mute]

right, so it's not for all 2-digit numbers, as earlier claimed. If the sum of the digits exceed 9, there's an extra step.

Which makes it more complicated than just simply multiplying. Or using a calculator.

That's the real beauty of math, proving/ disproving theorems and finding (or trying to find) universal truths.

oops sorry. nagmamadali siguro ako mag reply...

[Poundcake]

Point is, some "short-cuts" are not really shortcuts. In the x11 example, it's actually longer. You have to test the digits if they fall within a certain criterion. If yes, then do one thing. If not, do another thing (which consists of several iterations).

A "simpler shortcut" for x11 is multiply by 10 and add the same number. Thus 45 x 11 = 450+45 = 495. No if-then-else statement

That's how I do it as well. Not just with a multiplier of 11, but with other values as well. I agree that this method has less steps; it can be easily performed by most people with passable computational skills if the numbers are small but it gets a bit hairy for 'em numerically-challenged folks if the numerical values are higher. They prefer kabisote-style prodecures

And just for argument's sake, people who have a "knack for numbers" may not be necessarily good in mathematics. They may be good in arithmetic, but not in the other branches of mathematics, which require logic and analysis.

That's why I only mentioned basic arithmetic. That was what jm the mute and I were talking about in the first place

Which brings me to your "contributing to this thread" statement. I've been "contributing to this thread" by verifying and analyzing the logic of the "math tricks". That is the essence of mathematics, after all.

Sensible posts are always appreciated in PhilMusic. But what I meant was that if you have other mental math tricks to share, then please feel free to do so

Anyway, here's a nice website for math practice: https://brilliant.org/

Anybody already signed up at Brilliant.org?

[dariusbabylon]

ok. Please check your earlier posts, then.  And try to be more precise in your statements. Otherwise, it may sound like you're contradicting yourself. That's another math tip, by the way.