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The equation that broke the Internet

5,930 bytes added, 21:14, 30 March 2022
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'''6÷2(1+2)=?''' is the pre-algebra question that a majority of many Internet respondents seem to get wrong. If you are in the camp that knows the correct answer is 1, read no further. If you believe the answer is 9, you should probably review this document -- {{highlight|there is only one number that 6 can be divided by to result in 9, and that number is 2/3.}}
==Proof incorrect solution ==
We substitute x for 2(1+2) from the given equationand backtest the equation with the result of 9:
If
:6÷9 = x
there is a Common Denominator common divisor of 3 so we reduce the fraction...
:2÷3 = x
Now we compare the value given in the equation to the value we find found (above) for x.
:2÷3 '''!=''' 2(1+2)
:6÷2(1+2) '''!=''' 9
 
<p style="text-align:center;"> {{highlight|Without fail, 2(1+2) will always equal (2*1 + 2*2), this is the '''Distributive Law.'''}}</p>
 
== Proof of correct solution ==
''Encyclopedia Britannica'':
<blockquote>
::'''''Distributive law''''', ''in mathematics, the law relating the operations of multiplication and addition, stated symbolically, a(b + c) = ab + ac; that is, the monomial factor a is distributed, or separately applied, to each term of the binomial factor b + c, resulting in the product ab + ac.''
::&ndash;[https://www.britannica.com/science/distributive-law Encyclopedia Britticana]
</blockquote>
 
Therefore, in 6÷2(1+2)=?, we start with the <span style="color:green;"> Distributive Law</span> in the <span style="color:green;">Parenthesis</span> step of the Order of Operations.
 
::'''6÷2(1+2)=?'''
::'''6÷<span style="color:green;">(2*1 + 2*2)</span>=?'''
::'''6÷(2 + 4)=?'''
::'''6÷(6)=?'''
::'''6÷6=1'''
==Processing rules==
In the majority of incorrect proofs, the respondent will cite PEMDAS or BODMAS, however these solvers we all agree that parentheses or brackets are processed first. However, some respondents incorrectly resolve the [P]arentheses or [B]rackets of PEMDAS - BODMAS, ignoring the Distributive Law. For for some reason, they these solvers believe that they can solve resolve within the parentheses, but ignore neglect to multiply the adjacent and dependent coefficient.  === PEMDAS ===<blockquote> ::P parenthesis::E exponentiation::M multiplication::D division::A addition::S subtraction ::&ndash;[https://mathworld.wolfram.com/PEMDAS.html Wolfram PEMDAS]</blockquote>
=== Parentheses ===''Wolfram Mathworld'' confirms that this is the way we handle on parenthetical expressions:
<blockquote>
:: 1. ''Parentheses are used in mathematical expressions to denote modifications to normal order of operations (precedence rules)...''
::[...]
::3. ''Parentheses are used to enclose the variables of a function in the form f(x), which means that values of the function f are dependent upon the values of x.''
::&ndash;[http://mathworld.wolfram.com/Parenthesis.html Wolfram Parenthesis]
</blockquote>
===Distributive law===
''Encyclopedia Britannica'' on parenthetical expressions:
<blockquote>
::'''''Distributive law''''', ''in mathematics, the law relating the operations of multiplication and addition, stated symbolically, a(b + c) = ab + ac; that is, the monomial factor a is distributed, or separately applied, to each term of the binomial factor b + c, resulting in the product ab + ac.''
::&ndash;[https://www.britannica.com/science/distributive-law Encyclopedia Britticana]
</blockquote>
<!--
Therefore, in 6÷2(1+2)=?, we start with the Distributive Law in the <span style="color:green;">Parenthesis</span> step of the Order of Operations.
Therefore, in ::'''6÷2(1+2)=?, we start with the Distributive Law in the Parenthesis step of the Order of Operations.'''::'''6÷<span style="color:green;">(2*1 + 2*2)</span>=?'''
::'''6÷(2 + 4)=?'''
::'''6÷(6)=?'''
::<s>'''<div style="color:red;">6÷2*(3)</div>'''</s>
Correct processing:::<s>'''<div style="color:greenred;">3*(2*1 + 2*23)</div>'''</s>-->=== Parenthetical expressions ===
=== The Fundamentals of Algebra (1983) ===
<blockquote>
{{Quote|text=
''Parenthetical Expression. The parenthesis was described in Chapter 1 as a grouping symbol. When an algebraic expression is enclosed by a parenthesis it is known as a parenthetical expression. '''When a parenthetical expression is immediately preceded by coefficient, the parenthetical expression is a factor and <u>must be multiplied by the coefficient.</u>''' This is done in the following manner.''
::''5(a + b) = 5a + 5b'' <br/>
::''3a(b - c) = 3ab - 3ac''
</blockquote>
==The equation is not ambiguous =====6÷2(1+2) is not equal to 6÷2*Explicit vs Implicit (1+2implied)multiplication ==<div style="text-align:center">Standing alone, 6 will always equal 6 and 2(1+2) will also always equal six, so dividing these two terms will always equal 1. We would not write 2({{Quote|text='''''Implied multiplication''' has a+b) as (2(a+b))higher priority than explicit multiplication to allow users to enter expressions, nor would we re-write in the given equation same manner as 6÷2*(a+b)they would be written. Granted, the ''<br/> &ndash;[https://wwwepsstore.wyzantti.com/resourcesOA_HTML/blogscsksxvm.jsp?nSetId=103110 Implied Multiplication Versus Explicit Multiplication on TI Graphing Calculators] }}</14831/the_obelus_for_division obelus div> Explicit operations have explicit operators (* ÷+ - )] which are delimiters that divide equations into separate terms. Implied multiplication is notation that informs us that the value of a variable, bracketed function or exponent are connected and not separate terms. ''Implied multiplication is an archaic symbol for divisioneverywhere, 1x = x and x/1=x. Any number times 1 is that number and any number divided by 1 is that number.'' Implied multiplication is also implicit multiplication. {{Quote|text='''im·plic·it''' ''adjective'' :1. implied though not plainly expressed. :2. essentially or very closely connected with; always to be found in. '''im·plied''' ''adjective'' :1. suggested but this is not a postgraduate level equationdirectly expressed; implicit. '''ex·plic·it''' ''adjective'' :1. stated clearly and in detail, this is middle-school level mathleaving no room for confusion or doubt.
2(1+2) is understood to be a function, placing this function anywhere in a larger equation must always resolve to the same value. The equation, 6÷2(1+2)=? is illustrative to why we cannot substitute explicit multiplication for implied multiplication, in other words, 6÷2(1+2) is not equal to 6÷2*(1+2).&ndash;Oxford}}
{{Quote|text=''Implied multiplication 6÷2(1+2) has a higher priority than explicit two EXPLICIT operators, division and addition. However, IMPLIED multiplication tells us to allow users to enter expressionsIMPLICITLY multiply, [2(2+1)], in the same manner as they would be writtenP step of PEMDAS. In the division step, we must apply division to the (entire) implicitly connected parenthetical expression. We cannot apply division to the coefficient (2) and then not apply division to the factor (2+1).''<br/>
&ndash'''Incorrect:''' (''because division is not EXPLICITLY applied to the entire parenthetical expression'')<div style="color:red;"><div style="width:60px; text-align:center; float:left;[https">6 ---- 2 </div><div style="width:60px; text-align:center; float:left;"><br/><nowiki>*</nowiki><br/></div> <div style="width:60px; text-align:center; float:left;"><br/>(2+1)<br/epsstore.ti.com></OA_HTMLdiv> <div style="width:60px; text-align:center; float:left;"><br/csksxvm.jsp?nSetId>=103110 Implied Multiplication Versus Explicit Multiplication on TI Graphing Calculators] }}<br/></div> <div style="width:60px; text-align:center; float:left;"><br/>3 * (1+2) <br/> </div></div></div><div style="clear:both;"></div>
'''Correct:''' (''when EXPLICIT division is applied, it is applied to the entire term.'')<div style="color:green;"><div style=Correctly solving "width:60px; text-align:center; float:left to right=;">6 ---- 1 </div><div style="width:60px; text-align:center; float:left;"><br/>÷<br/></div>
If we insist on a <div style="width:60px; text-align:center; float:left to right solution, ignoring both PEMDAS and the Distributive Law, we can do this with the Least Common Denominator rule;">2(1+2) ---- 1 </div>
<div style="width:60px; text-align:''6÷2(1+2)=?''center; float:left;"><br/>::''3÷(1+2)=?''::''3÷(3)=?''<br/>::''3÷3=1''</div>
When we reduce by the common denominator, the division is sustained... <div style="width:60px; text-align:center; float:left;">2 * (1+2) ---- 6 * 1 </div></div></div><div style="clear:both;"></div>
==Solution written as a fraction ==In the denominator, both the coefficient and the factor must be divided in the following manner. '''Traditional solution:'''
<div style="color:green;"><div style="width:100px60px; text-align:center; float:left;">
6
----
2(1+2)
</div>
<div style="width:100px60px; text-align:center; float:left;">
<br/>
=
</div>
<div style="width:100px60px; text-align:center; float:left;">
3
----
1*(1+2)
</div>
<div style="width:100px60px; text-align:center; float:left;">
<br/>
=
</div>
<div style="width:100px60px; text-align:center; float:left;">
3
----
</div>
<div style="width:100px60px; text-align:center; float:left;">
<br/>
= 1
<br/>
</div>
</div>
<div style="clear:both;"></div>
 
<!--
As we can see, we cannot add an EXPLICIT operator to 6÷2(1+2) without maintaining the IMPLICIT relationship that was stated with IMPLIED multiplication. 6÷2(1+2) == 6÷(2*(1+2)).
-->
 
==Correctly solving left to right==
 
If we insist on a left to right solution, ignoring both PEMDAS and the Distributive Law, we can do this by expressing the common divisor first. However, division is sustained and must be applied to everything to the right of the explicit division operator.
 
::''6÷2(1+2)=?''
::''3÷1(1+2)=?''
::''3÷(1+2)=?''
::''3÷(3)=?''
::''3÷3=1''
 
When we reduce by the common divisor, this does not complete the division operation, it simply reduces the coefficient to one. Division must be applied to both the factor and the coefficient of the parenthetical expression.
 
==The equation is not ambiguous ==
===6÷2(1+2) is not equal to 6÷2*(1+2)===
Standing alone, 6 will always equal 6 and 2(1+2) will also always equal 6, so dividing these two terms will always equal 1.
 
We would not write 2(a+b) as (2(a+b)), nor can we re-write the given equation as 6÷2*(a+b) and maintain the same value. We can however, rewrite the full equation to include an explicit multiplier if we take care to maintain the parenthetical expression with additional bracketing 6÷(2*(a+b)).
 
=== Obelus ===
Granted, the [https://web.archive.org/web/20210417145938/https://www.wyzant.com/resources/blogs/14831/the_obelus_for_division obelus (÷)] is an archaic symbol for division, it visually represents a fraction with one dot being the numerator and the other being the denominator. Computers use the forward slash for division because the standard keyboard does not have an obelus key.
 
For those who claim that the obelus is outdated, why then is it present on virtually every modern calculator?
== The calculator problem ==
The [https://www.desmos.com/scientific Desmos Scientific Calculator] handles our given equation correctly. The error checking appears to be built into the division key.
Entering the equation into a programming language, or low quality calculator , requires the explicit multiplication symbol and outer parenthesisto maintain value of the parenthetical expression.
'''6÷2(1+2) == 6÷(2*(1+2))'''
Other calculators, including Google and Wolfram will simply strip the parenthesis and solve a different equation, 6÷2*3. This is because within the programming, the open parenthesis (bracketing) triggers a different function within the programming, an open parenthesis tells the compiler to find the innermost parenthesized term and work outwards. Thus, to get the correct answer from inferior calculators, the input must be formalized with correct bracketing. I.e. 6÷(2*(1+2)) ==Spreadsheets==Entering the equation as =6/2(1+2) into a cell in a LibreOffice Calc spreadsheet will result in Err:509 (Missing operator) , Google Sheets also returns an error (Formula parse error). This forces the user to format the equation using explicit multiplication.To avoid the left to right problem, the compiler must be instructed in advance to prepare for the function with an extra pair of parenthesis =6/(2*(1+2)). ==See also==* [https://www.nytimes.com/2019/08/05/science/math-equation-pemdas-bodmas.html "That Vexing Math Equation? Here’s an Addition"]* [https://www.youtube.com/watch?v=hsZCtgFcL40 "How to Solve 8÷2(2+2) Using Implied Multiplication"]* [https://slate.com/technology/2013/03/facebook-math-problem-why-pemdas-doesnt-always-give-a-clear-answer.html "What Is the Answer to That Stupid Math Problem on Facebook?"]* [https://www.inc.com/dave-kerpen/this-basic-math-problem-is-breaking-internet.html This Basic Math Problem Is Breaking the Internet: How do you solve this simple arithmetic problem?]