How is rearranging 56 x 100 ÷ 8 into 56 ÷8 x100 allowed by the commutative property?
$begingroup$
So according to the commutative property for multiplication:
$a * b = b * a$
However this does not hold for division
$a ÷ b$ $!= b ÷a$
Why is it that in the following case:
$56 * 100 ÷ 8 = 56 ÷ 8* 100$
It seems like division is breaking the rule. There is something I am misunderstanding here.
Is it because $a*b÷c=a÷c*b$ is allowed since $b÷c$ are not being rearranged so that $c÷b$?
If this is the case are you allowed to rearrange values in equations so long as no values have the form $a ÷ b$ $= b ÷a$ and $a - b$ $= b -a$ ?
arithmetic
$endgroup$
add a comment |
$begingroup$
So according to the commutative property for multiplication:
$a * b = b * a$
However this does not hold for division
$a ÷ b$ $!= b ÷a$
Why is it that in the following case:
$56 * 100 ÷ 8 = 56 ÷ 8* 100$
It seems like division is breaking the rule. There is something I am misunderstanding here.
Is it because $a*b÷c=a÷c*b$ is allowed since $b÷c$ are not being rearranged so that $c÷b$?
If this is the case are you allowed to rearrange values in equations so long as no values have the form $a ÷ b$ $= b ÷a$ and $a - b$ $= b -a$ ?
arithmetic
$endgroup$
add a comment |
$begingroup$
So according to the commutative property for multiplication:
$a * b = b * a$
However this does not hold for division
$a ÷ b$ $!= b ÷a$
Why is it that in the following case:
$56 * 100 ÷ 8 = 56 ÷ 8* 100$
It seems like division is breaking the rule. There is something I am misunderstanding here.
Is it because $a*b÷c=a÷c*b$ is allowed since $b÷c$ are not being rearranged so that $c÷b$?
If this is the case are you allowed to rearrange values in equations so long as no values have the form $a ÷ b$ $= b ÷a$ and $a - b$ $= b -a$ ?
arithmetic
$endgroup$
So according to the commutative property for multiplication:
$a * b = b * a$
However this does not hold for division
$a ÷ b$ $!= b ÷a$
Why is it that in the following case:
$56 * 100 ÷ 8 = 56 ÷ 8* 100$
It seems like division is breaking the rule. There is something I am misunderstanding here.
Is it because $a*b÷c=a÷c*b$ is allowed since $b÷c$ are not being rearranged so that $c÷b$?
If this is the case are you allowed to rearrange values in equations so long as no values have the form $a ÷ b$ $= b ÷a$ and $a - b$ $= b -a$ ?
arithmetic
arithmetic
edited 41 mins ago
Sphygmomanometer
asked 43 mins ago
SphygmomanometerSphygmomanometer
717
717
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4 Answers
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$begingroup$
Notice that you have always $div 8$, no matter the order of the other terms. You don't divide by a different number. It might help to think $div c$ as a multiplication with $d=1/c$. Then everything would look easier:
$$atimes bdiv c=atimes btimes d=atimes dtimes b=adiv ctimes b$$
$endgroup$
add a comment |
$begingroup$
The non-zero real numbers form an abelian group under multiplication. The notation $adiv b$ is shorthand for $ab^{-1}$.
So $ab^{-1}ne ba^{-1}$ but $56times100 times8^{-1}=56times 8^{-1}times 100$
$endgroup$
add a comment |
$begingroup$
Hope this makes sense.
$$ atimes b ÷ c $$
$$=atimesdfrac{b}{c}$$
$$=atimes btimesdfrac{1}{c}$$
$$=(atimesdfrac{1}{c})times b$$
$$=dfrac{a}{c}times b$$
$$=a÷ctimes b$$
New contributor
$endgroup$
add a comment |
$begingroup$
Because division is the inverse of multiplication, that is: $$X div Y =Xcdot frac 1Y$$
So you have: $$56cdot 100 cdot frac18 =56cdotfrac18cdot100$$
Which is obvious.
$endgroup$
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Notice that you have always $div 8$, no matter the order of the other terms. You don't divide by a different number. It might help to think $div c$ as a multiplication with $d=1/c$. Then everything would look easier:
$$atimes bdiv c=atimes btimes d=atimes dtimes b=adiv ctimes b$$
$endgroup$
add a comment |
$begingroup$
Notice that you have always $div 8$, no matter the order of the other terms. You don't divide by a different number. It might help to think $div c$ as a multiplication with $d=1/c$. Then everything would look easier:
$$atimes bdiv c=atimes btimes d=atimes dtimes b=adiv ctimes b$$
$endgroup$
add a comment |
$begingroup$
Notice that you have always $div 8$, no matter the order of the other terms. You don't divide by a different number. It might help to think $div c$ as a multiplication with $d=1/c$. Then everything would look easier:
$$atimes bdiv c=atimes btimes d=atimes dtimes b=adiv ctimes b$$
$endgroup$
Notice that you have always $div 8$, no matter the order of the other terms. You don't divide by a different number. It might help to think $div c$ as a multiplication with $d=1/c$. Then everything would look easier:
$$atimes bdiv c=atimes btimes d=atimes dtimes b=adiv ctimes b$$
answered 34 mins ago
AndreiAndrei
12.1k21127
12.1k21127
add a comment |
add a comment |
$begingroup$
The non-zero real numbers form an abelian group under multiplication. The notation $adiv b$ is shorthand for $ab^{-1}$.
So $ab^{-1}ne ba^{-1}$ but $56times100 times8^{-1}=56times 8^{-1}times 100$
$endgroup$
add a comment |
$begingroup$
The non-zero real numbers form an abelian group under multiplication. The notation $adiv b$ is shorthand for $ab^{-1}$.
So $ab^{-1}ne ba^{-1}$ but $56times100 times8^{-1}=56times 8^{-1}times 100$
$endgroup$
add a comment |
$begingroup$
The non-zero real numbers form an abelian group under multiplication. The notation $adiv b$ is shorthand for $ab^{-1}$.
So $ab^{-1}ne ba^{-1}$ but $56times100 times8^{-1}=56times 8^{-1}times 100$
$endgroup$
The non-zero real numbers form an abelian group under multiplication. The notation $adiv b$ is shorthand for $ab^{-1}$.
So $ab^{-1}ne ba^{-1}$ but $56times100 times8^{-1}=56times 8^{-1}times 100$
answered 34 mins ago
Angela RichardsonAngela Richardson
5,28911733
5,28911733
add a comment |
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$begingroup$
Hope this makes sense.
$$ atimes b ÷ c $$
$$=atimesdfrac{b}{c}$$
$$=atimes btimesdfrac{1}{c}$$
$$=(atimesdfrac{1}{c})times b$$
$$=dfrac{a}{c}times b$$
$$=a÷ctimes b$$
New contributor
$endgroup$
add a comment |
$begingroup$
Hope this makes sense.
$$ atimes b ÷ c $$
$$=atimesdfrac{b}{c}$$
$$=atimes btimesdfrac{1}{c}$$
$$=(atimesdfrac{1}{c})times b$$
$$=dfrac{a}{c}times b$$
$$=a÷ctimes b$$
New contributor
$endgroup$
add a comment |
$begingroup$
Hope this makes sense.
$$ atimes b ÷ c $$
$$=atimesdfrac{b}{c}$$
$$=atimes btimesdfrac{1}{c}$$
$$=(atimesdfrac{1}{c})times b$$
$$=dfrac{a}{c}times b$$
$$=a÷ctimes b$$
New contributor
$endgroup$
Hope this makes sense.
$$ atimes b ÷ c $$
$$=atimesdfrac{b}{c}$$
$$=atimes btimesdfrac{1}{c}$$
$$=(atimesdfrac{1}{c})times b$$
$$=dfrac{a}{c}times b$$
$$=a÷ctimes b$$
New contributor
New contributor
answered 29 mins ago
AdityaAditya
112
112
New contributor
New contributor
add a comment |
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$begingroup$
Because division is the inverse of multiplication, that is: $$X div Y =Xcdot frac 1Y$$
So you have: $$56cdot 100 cdot frac18 =56cdotfrac18cdot100$$
Which is obvious.
$endgroup$
add a comment |
$begingroup$
Because division is the inverse of multiplication, that is: $$X div Y =Xcdot frac 1Y$$
So you have: $$56cdot 100 cdot frac18 =56cdotfrac18cdot100$$
Which is obvious.
$endgroup$
add a comment |
$begingroup$
Because division is the inverse of multiplication, that is: $$X div Y =Xcdot frac 1Y$$
So you have: $$56cdot 100 cdot frac18 =56cdotfrac18cdot100$$
Which is obvious.
$endgroup$
Because division is the inverse of multiplication, that is: $$X div Y =Xcdot frac 1Y$$
So you have: $$56cdot 100 cdot frac18 =56cdotfrac18cdot100$$
Which is obvious.
answered 29 mins ago
Rhys HughesRhys Hughes
6,7101530
6,7101530
add a comment |
add a comment |
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