Maths Q

[bryan1]

40 + 40 x 0 + 1 = ?



A) 0
B) 41
C) 1
D) 81

Post your answer......

 

[DerStrom8]

Definitely B

 

[Sceadwian]

Yep 41.

 

[ARandomOWl]

Not another one...at least this might not result in such an argument

 

[DerStrom8]

Not another one...at least this might not result in such an argument

Yep, this is one with a very definite answer that cannot be debated

 

[KeepItSimpleStupid]

B, unless you redefined the + and x operators to mean something else.

 

[Mickster]

I'll go with C

 

[MrAl]

Hi,


It depends on what rules you are abiding by...

By the rules of algebra, the correct answer is B) 41.
But if you are going by the pure left to right rules then the answer will be different.

However, in the case where there is a lack of context the rules of algebra would normally be assumed (no previous definitions given).

I've seen calculators that will give the answer as 41 and those that would give the answer as 1. Most modern calculators will give the answer as 41.

 

[JimB]

The answer to the ambiguity problem is that any decent engineer or technical writer would put the expression in a form which was un-ambiguous.

Possible combinations are:
((40 + 40) x 0) + 1 = 1

(40 + (40 x 0)) + 1 = 41

(40 + 40) x (0 + 1) = 80

The answer to the question originally posed by bryan1 is 41 (B).
(Using the BODMAS convention).

JimB

 

[Mikebits]

Anything times 0 is 0 so I go with C.

 

[Mickster]

Anything times 0 is 0 so I go with C.

That was my conclusion too, Mike.

 

[DerStrom8]

Anything times 0 is 0 so I go with C.

But don't forget the PEMDAS order of operations. Multiplication and division must come first, THEN addition and subtraction. The multiplication (40x0) comes first, so you come up with 40+(0)+1. From there, it's self explanatory.

 

[Mickster]

There are no parentheses in this question.

 

[DerStrom8]

There are no parentheses in this question.

No, but because of the order of operations, the parentheses are not necessary. PEMDAS, of course, stands for Parentheses, Exponents, Multiplication/Division, Addition/Subtraction. That is the order that a math problem must be completed in. Therefore, since Multiplication comes before Addition, you must do the multiplication of 40x0 first. This is a universal rule of mathematics.

 

[duffy]

Derstrom8 is right, of course, and it's scary how many people get this wrong, this is third-grade math. This question is making the rounds on Facebook, and MOST people are choosing the wrong answer!

 

[Mickster]

At what point do the mathematical rules change?

When I went to school (many years ago) and had to undertake the basic maths lessons taught to all and sundry, there was no mention whatsoever of PEMDAS/BODMAS or any other derivative of acronyms. There was basic maths for the normal kids and higher maths for the geeky ones.

We had some encounters with algebra, but there was no mention that certain rules apply to mathematical equations not containing parentheses.

Do yourselves a test:
Open a calculator in Windows.
Do the calculation on a standard calculator.
Then do it again on a scientific calculator.

Why should the result be different?

 

[KeepItSimpleStupid]

I have an early calculator called the TI SR-10 and it would just evaluate from left to right. The buttons act immediately.

I personally like RPN (reverse Polish Notation), so 40 + 40 x 0 + 1 =

Would be encoded as 40 0 * 40 + 1 +

 

[duffy]

[LATEX]40+40x[/LATEX]

So some of you are saying you think that equals zero when x = 0. Sad.

 

[DerStrom8]

Do yourselves a test:
Open a calculator in Windows.
Do the calculation on a standard calculator.
Then do it again on a scientific calculator.

Why should the result be different?

Some calculators have PEMDAS/BODMAS programmed into them, whereas others require you to know it already. Generally it's the newer ones that have it programmed in already. That's my experience, anyway.

 

[squishy36]

Unfortunately, questions such as these are a waste of time because they cause people to argue over precedence. So the correct answer is "state the precedence rules you want to use first -- then it's easy to calculate the answer.