In my head in a few seconds. 12 divided by 8 = 1.5 over 2 X 4 = 8. So 1.5 over 8 is not one of the answers. But 3 over 16 is = to 1.5 over 8. In a calculator both answers = 0.1875
Was really expertly broken down to explain the principles. I learned how the division sign can be used to separate in brackets. Another way could be to use the inverse/flip principle (explained at 13:15 in the video) and just put the 8 to the bottom, so the denominator becomes 2 x 4 x 8, with 12 as the numerator. 12/64 is then 3/16.
the long fraction line acts like parentheses -- i.e. (12/8) ÷ (2×4) =(6/4) ÷ (8) = (3/2) ÷ (8) my recent finding is that it's less error prone to replace "÷y" with "×(1/y)" so = (3/2) ÷ (8) = (3/2) × (1/8) = 3/16
Mental math for multiple choice: See that 12/8 will be between 1 and 2. See that the bottom is 8 So the answer will be a fraction less than 1. Choose 3/16. Mental math exact: Top part reduces to 3/2 Bottom part is 8 Divide by 8 is the same as × 1/8 3/2 × 1/8 = 3/16
Factor programming language: 12 8 / Data Stack-> 1+1/2 2 4 * Data Stack-> 1+1/2 8 / Data Stack-> 3/16 Python programming language: >>> (12/8)/(2*4) 0.1875 Excel spreadsheet: =(12/8)/(2*4) 0.1875 Paper and pencil: (12/8) = ----------------- (2*4) (12/8) = ----------------- 8 = [12/(8*8)] = 12/64 = (3*4)/(16*4) = 3/16 Common sense: 1.5/8 = a number less than 1, and only d) of the multiple choice is less than 1
[12 : 8] / [2 · 4] [12/8] / [8] dividing by a number is the same as multiplying by its reciprocal reciprocal of a --> 1/a , reciprocal of 3/4 --> 4/3 a : b = a · 1/b 12/8 · 1/8 = 12/64 = 3/16✅ -> d
This is a simple fraction problem: 12/8 divided by 8/1 = 12/8x1/8 = 12/64 = 3/16 , PEMDAS has nothing to do with it unless you only know how to use a calculator. PEMDAS makes it more complicated, just learn math without a calculator and you will be much smarter.
got 3/16 in my head 1.5 / 8 1.5 = 3/2 to divide by 8, multiply by 1/8 so 3/2 X 1/8 multiply accross = 3/16. thanks for the fun. afterward, i put 1.5 / 8 into a calc and got the decimal version of 3/16 as .1875. it does work.
@enriqueiii9209 but I request you to do mental math stepwise and those steps should follow some specific rule with their exception as well under certain conditions as in this problem.
In my head in a few seconds. 12 divided by 8 = 1.5 over 2 X 4 = 8. So 1.5 over 8 is not one of the answers. But 3 over 16 is = to 1.5 over 8. In a calculator both answers = 0.1875
I doubled them. 1.5/8 = 3/16.
Was really expertly broken down to explain the principles. I learned how the division sign can be used to separate in brackets. Another way could be to use the inverse/flip principle (explained at 13:15 in the video) and just put the 8 to the bottom, so the denominator becomes 2 x 4 x 8, with 12 as the numerator. 12/64 is then 3/16.
the long fraction line acts like parentheses --
i.e.
(12/8) ÷ (2×4)
=(6/4) ÷ (8)
= (3/2) ÷ (8)
my recent finding is that it's less error prone to replace
"÷y" with "×(1/y)"
so
= (3/2) ÷ (8)
= (3/2) × (1/8)
= 3/16
I'm astonished that I still remembered how to do this at 68, but I went straight there.
Well done me.
I can't believe it takes 15 minutes to explain this.
Mental math for multiple choice:
See that 12/8 will be between 1 and 2.
See that the bottom is 8
So the answer will be a fraction less than 1. Choose 3/16.
Mental math exact:
Top part reduces to 3/2
Bottom part is 8
Divide by 8 is the same as × 1/8
3/2 × 1/8 = 3/16
One can quickly see that the answer has to be less than 1 and therefore there’s only one choice, 3/16.
Answer: 3/16
-------
12 ➗ 8
-----
2 x 4
3/2
--
8
3 x 1
- --
2 8
3
---
16
Thank you for bringing back classical, common sense mathematic theory.
Factor programming language:
12 8 /
Data Stack-> 1+1/2
2 4 *
Data Stack-> 1+1/2
8
/
Data Stack-> 3/16
Python programming language:
>>> (12/8)/(2*4)
0.1875
Excel spreadsheet:
=(12/8)/(2*4)
0.1875
Paper and pencil:
(12/8)
= -----------------
(2*4)
(12/8)
= -----------------
8
= [12/(8*8)]
= 12/64
= (3*4)/(16*4)
= 3/16
Common sense:
1.5/8 = a number less than 1, and only d) of the multiple choice is less than 1
[12 : 8] / [2 · 4]
[12/8] / [8]
dividing by a number is the same
as multiplying by its reciprocal
reciprocal of a --> 1/a , reciprocal of 3/4 --> 4/3
a : b = a · 1/b
12/8 · 1/8 = 12/64 = 3/16✅ -> d
Or use an RPN calculator. 12 [Enter]8[÷]2[Enter]4[×][÷]
Yielding 0.1875 or 3/16.
Or manually:
12 ÷ 8 => 3/2
4 × 2 => 8
3/2 ÷ 8 => 3/2 × 1/8 => 3/16
(12/8) / 8 = (12/8) / (8/1) = (12 X 1) / ( 8 X 8) = 12/64 = 3/16
( ps : (a/b) / ( c/d) = (a X d) / (b X c)
This is a simple fraction problem: 12/8 divided by 8/1 = 12/8x1/8 = 12/64 = 3/16 , PEMDAS has nothing to do with it unless you only know how to use a calculator. PEMDAS makes it more complicated, just learn math without a calculator and you will be much smarter.
got 3/16 in my head 1.5 / 8 1.5 = 3/2 to divide by 8, multiply by 1/8 so 3/2 X 1/8 multiply accross = 3/16.
thanks for the fun.
afterward, i put 1.5 / 8 into a calc and got the decimal version of 3/16 as .1875. it does work.
I just saw the answers, 3/16
(12/8)/(2*4) = (3/2)/8 = 3/16 Answer d. took me roughly 20 secs, answer at 13:20 You go figure it out how much time you need .... CHEERS🍺🍻
I've always found a good way is to just write x/y / a/b then multiply both sides by each denominator
which in this case results in 12/64
@@williamarthur4801 next, reduce the fraction and you will match one of the answer choices.
(12/8)/(2 · 4) = (3/2)/8 = 3/16 = d.
DO THE NUMERATOR AND DENOMINATOR SEPARATELY. ANSWER IS 3/16 ON SIMPLIFICATION.
USING PARENTHESES.
PARENTHESIS HELPS SEPARATE THE NUMERATOR FROM THE DENOMINATOR
12/8 * 1/8 / 8/1 *1/8 = 12/64 / 1 = 3/16
1.5 divided 8 = 3/16
D: 3/16
12 / (8 . 2 . 4) = 3/16
d 3/16
(12/8)/(2*4)=0.1875=3/16
Mental maths could only have been 1 answer anyway.
Agree, Common sense
Doesn't mental math need some rules ( PEMDAS/BODMAS ) to be followed?
@@khadim-qg8bq Not for this problem.
@enriqueiii9209 but I request you to do mental math stepwise and those steps should follow some specific rule with their exception as well under certain conditions as in this problem.
@@khadim-qg8bq I did do Mental math in my head.
C) 12
Viniculum - that word keeps coming up.
3/16...(d) ans
d) 3/16
3/16 d
You can't get a whole number? so the only correct answer is d 3/16
D is right answer
Got 3/16 doing it in my head, calculator said 3.
Ah…thanks so much. This helps!
3/16th? Thank you
This was known as cross multiplying when I learned it. 😊
D is my answer
I did it in my head and came up with d) 3/16
.25/8=3
25
3/16 or 0.1875
12😊
😮 I swear to you....I got 3/16 and I kant understand how da hell I got it right and I haven't been in skool in 11 years
The answer is 3
D
Get to the point without all the waffle
3
3/16
Can we mind meld Mr Spock?
12 div by 8 = 1.5
1.5 div by 8 = 0.1875, therefore the answer has to be a fraction.
0.1875 = 3/16
d
Another prime example of the ambiguity of math.
Mathmegaincians being stingy with chalk.
You must be watching a different video. There's absolutely no ambiguity here.
It is only ambiguous if you don't know basic math. You must evaluate the top part abs the bottom part first, then divide.
12
No a plus for me😢
I solved it in 0.0000001 seconds
= 12
That's what I was thinking
awesome video!! thank you !! 😎😎😎😎
d) 3/16
D
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