## A simple math problem/puzzle

Discussions concerned with knowledge of measurement, properties, and relations quantities, theoretical or applied.

## Which is the correct solution for: 6 - 1 x 0 + 2 / 2 = ?

3
23%
7
54%
3
23%
0
Other
0

### A simple math problem/puzzle

Hi everyone,

This problem is floating around the Internet lately and I'd like some input.

Regards,

Dave :^)

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### Re: A simple math problem/puzzle

Is something missing?

Watson
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### Re: A simple math problem/puzzle

Easy does it - slowly and carefully. :-)
vivian maxine
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### Re: A simple math problem/puzzle

Can't I say what I voted for?
uninfinite
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### Re: A simple math problem/puzzle

I am presuming Dave's comment "Please select an answer first before reading the comments below." is based on the expectation that posters will explain how they arrived at their answer.

If you don't want to know, look away now......

Multiplication and division must be conducted first, so the expression becomes

6 - 0 + 1

Eclogite
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### Re: A simple math problem/puzzle

ecoglite wrote:Multiplication and division must be conducted first

Is this a fact in math? I didn't know that. I thought, with no parenthetical divisions, it was read as a straight sentence. I'm wrong? :-(
vivian maxine
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### Re: A simple math problem/puzzle

I just read from left to right:

6-1=5x0=0
+2/2(=1)

If you'd wanted it to read 6 - (1x0) should have included the brackets!
uninfinite
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### Re: A simple math problem/puzzle

uninfinite » April 29th, 2016, 10:04 am wrote:I just read from left to right:

6-1=5x0=0
+2/2(=1)

If you'd wanted it to read 6 - (1x0) should have included the brackets!

Now I feel better. That is what I did, uninfinite. I'm sure it's what we were taught. With no brackets, read it as a sentence. 6 - 1 = 5 x 0 = 0 + 1. Answer = 1. With brackets, solve those included parts first.

Where is my old math book when I need it?
vivian maxine
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### Re: A simple math problem/puzzle

vivian maxine » April 29th, 2016, 4:13 pm wrote:
uninfinite » April 29th, 2016, 10:04 am wrote:I just read from left to right:

6-1=5x0=0
+2/2(=1)

If you'd wanted it to read 6 - (1x0) should have included the brackets!

Now I feel better. That is what I did, uninfinite. I'm sure it's what we were taught. With no brackets, read it as a sentence. 6 - 1 = 5 x 0 = 0 + 1. Answer = 1. With brackets, solve those included parts first.

Where is my old math book when I need it?

Yeah! And anyway - why specify 6 - 1x0 - when you could just write 6 - 0, or indeed just write 6 and leave it at that?

We got it right!
uninfinite
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### Re: A simple math problem/puzzle

uninfinite » Fri Apr 29, 2016 3:04 pm wrote:If you'd wanted it to read 6 - (1x0) should have included the brackets!
It is wise to add the brackets to avoid ambiguity, but they are there implicitly, as they are for division signs. Do you use Excel?
Eclogite
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### Re: A simple math problem/puzzle

I still prefer the simple life. Glad I'm not a mathematician.
vivian maxine
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### Re: A simple math problem/puzzle

I'm happy to accept I'm wrong - if you know more maths than I do, and it's likely you do, for while not impossible, it's improbable you could know less. In my education, many years ago now - I seemed to do okay until they started mixing letters in with the numbers and my brain just rebelled. Words is words and numbers is numbers!

n squared.

nn
nn.

No?
uninfinite
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### Re: A simple math problem/puzzle

I was taught that multiplicative statements assume their own brackets, so I got 7. I don't think there's a "right" answer, only answers that indicate what formal conventions you were taught. The problem is really just a way of saying "brackets are handy!"

Braininvat
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### Re: A simple math problem/puzzle

Hi Everyone,

In College, 45 years ago, we were taught this Math expression is pure Garbage, as is evidenced by the number of different answers.

One calculator will resolve it to (1) and another calculator will resolve it to 7. But if faced with this kind of problem, one must auto bracket the additions and subtractions first, as that's the way its been done for 100's of years and thus would produce the value 5, which is the correct answer (before someone decided to muddy up the water).

Want proof?

Take for example an Ohms Law problem of two Resistors tied in Parallel. The solution is called "Product over the Sum". Let's say both Resistors were 5 ohms each. Thus the solution would be 2.5 ohms and it would be expressed as (5x5)/(5+5)=2.5. ohms.

Now, if I remove the brackets, it would look like 5x5/5+5=10, and based on the the idea of doing Multiply and Divide first, without auto-brackets, would produce what is obviously the wrong answer of 10.

Math is a precise language and it must be absolutely clear or it is plain Garbage.

Regards..

Dave :^)

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### Re: A simple math problem/puzzle

Eclogite » April 29th, 2016, 3:44 pm wrote:Multiplication and division must be conducted first

That is what I was taught at school – and Wikipedia agrees:

http://en.wikipedia.org/wiki/Order_of_operations
Positor
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### Re: A simple math problem/puzzle

Hi Positor,

You got it.. I'm busted.. lol.

You are correct, but a problem stated as such must have brackets to force a procedural order. If one was to put brackets around my problem based on Multiply/Divide then (5*5)/(5+5) = 5*5/5+5 = ((5x5)/5)+5 = 10 and is the wrong answer. But given 5x5/5+2 = 5x5/(5+5) with brackets, the solution become 2.5, which is correct.

But honestly.. here is another way to express my problem 1/((1/5)+(1/5)) = 2.5 using reciprocals. This would become 1/1/5+1/5 = 1/1/(5+1)/5 = 0.033333 which is still wrong.

There is no rule for automatically placing Brackets as shown above. Automatically putting brackets around (x & /) or (+ & -) is still subject to being incorrect. So the solution hierarchy requires brackets.. to be perfectly clear in what order the problem is solved.

Wiki wrote: In the United States the acronym PEMDAS is common. It stands for Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.

Knowing this, the solution above is actually (7) because brackets are not supplied. Granted, convention exists to handle this, but this problem format was considered sloppy and undesirable back when I was in school.

Not supplying Brackets is worse than not spelling words properly.. IMHO ;^P

Best wishes all,
Dave :^)

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### Re: A simple math problem/puzzle

Eclogite » April 29th, 2016, 10:36 am wrote:
uninfinite » Fri Apr 29, 2016 3:04 pm wrote:If you'd wanted it to read 6 - (1x0) should have included the brackets!
It is wise to add the brackets to avoid ambiguity, but they are there implicitly, as they are for division signs. Do you use Excel?

Ecoglite, forgive my returning to a worn-out topic but I remembered something this morning and I must ask:

Exactly where did you put your brackets?

6 (-1 x 0) ? Or 6 - (1 z 0) ?

Somewhere I read that the minus sign goes with the 1. If that is correct, then what I remember is this: 6 x (any numbers) means multiply. In fact, I don't think I ever saw a sign outside the brackets as I've done the second example.

So, what I remembered early this morning is that 6 (any combination you like) means multiply what is inside the brackets by 6. 6 x 0 + 1 = 1

Am I remembering wrongly? Don't we multiply what is inside the brackets by the preceding number? 4 (6 + 2) = 32. 3 ( 2 + 2) + 4 = 16.

vivian maxine
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### Re: A simple math problem/puzzle

Like Eclogite, I achieved 7 very quickly using the rule of multiplications and divisions having priority over additions and subtractions.

I assumed that this was International format now. Does anyone know of a variation from that rule?
doogles
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