I know bedmas. Shouldn’t it be left to right when tied?(multiplication and division). This would give 16.
In: Mathematics
Yes and no. This is a trick question which exploits an ambiguity between two different notation styles, one familiar from elementary school and a later one which we pick up around high school.
When kids are first learning arithmetic expressions, multiplication and division are denoted by the × and ÷ symbols. But around the time we start doing algebra, we stop using ÷ in favour of fraction bars, and we quit using × in favour of just sticking stuff together with no symbol, and from that point on you can start treating those multiplicative blobs as indivisible atoms and never have to think about the left-to-right MD step of PEMDAS again, because the fractional bars and layout tell you everything you need to know.
So when we see an expression which has a ÷ symbol *and* and one of those blob-multiplications (technically, ‘implicit multiplication by juxtaposition’), it’s meant to make us confused, like “wtf, do I read this the elementary school way, or the high school way?”
In some sources, this kind of implicit multiplication has an earlier precedence than a division symbol, and in others it doesn’t, so anyone insisting on a single clear right answer is missing part of the story. The real answer is that someone who knew what they were doing and actually *wanted* to communicate a mathematical expression clearly, would never write it that way. If you encountered this formula in real life, the right thing would be to track down who wrote it and ask what they meant.
This is a special case.
Because yes, this could be interpreted as:
(8/2)*4 =16
or
8/(2*4) =1
But what you have here is called “implied multiplication” because you haven’t actually written 2*4. Implied multiplication is done before division (sometimes, I’m not sure that universal)
This feels like homework help… but:
You do the brackets first so: 2+2=4
Then you multiply what’s in the brackets by (in this case) 2, so: 2*4=8
Then divide: 8÷8=1
8/[2(2+2)] = 8/2(4) = 8/8 = 1
Parentheses – (2+2) = 4
Exponents – N/A
Multiplication -2(4)
Division – 8/8
Addition – N/A (addition is under parentheses)
Subtraction -N/A
This is a certain equality.
In math, parenthesis executes first, then multiplication/division, then adding and substracting.
So:
8/2*(2+2)=1
8/2*(4)=1
8/8=1
Which is true.
I actually just made a [post on YSK ](https://www.reddit.com/r/YouShouldKnow/comments/jydtc6/ysk_the_difference_between_an_obelus_and_a/?utm_source=share&utm_medium=ios_app&utm_name=iossmf) about exactly this! The key is the division symbol being an **obelus** in the equation. Because an **obelus** follows PEMDAS, the procedure is 8 divided by 2 (4). Then 4 times 2+2 which would give us 16. Had the division symbol been a **Vinculum**, the answer would be 1. The post explains a little more in depth the differences between the symbols. Hope this helps!
I did some schooling in South Africa. We called it Bodmas. Lol. Brackets of multiplication, division, addition and subtraction.
Brackets first, and number next to bracket immediately after, followed by what’s on the left.
This nonsense again.
The issue is the obelus **÷** which is usually misinterpreted as the same as / which it is not. Its one of the reasons ÷ is no longer used. When the ÷ is used, its indicating a fraction, where the values to the right are the denominator (and since there is only 1 term before ÷ we know thats the numerator). This isn’t a trick question, its just written using poor methods hoping you don’t know the proper use of ÷
This equation without the ÷ symbol is better written as’
8 8
——– = —– = 1
2*(2+2) 8
When you see it that way, its quite easy to see the answer.
The equation has extra implied operators that are not clear.
8÷2(2+2)=1
The first implied operator is clear. There 2 is multiplying (2+2)
8÷2*(2+2)=1
But the problem is that there are also implied parenthesises around it.
8÷(2*(2+2))=1
These implied parenthesises are more common with variables.
For example:
3/2x has the same implied parenthesises and multiplication. It is same as 3/(2x).
These implied parenthesises are ambiguous. So ambiguous that you can’t really expect a person to notice them. This equation is written so badly that you can’t be certain what it really means.
The correct answer is to ask for clarification.
This kind of implied parenthesises notation should not be used for anything other than single variables like the example earlier.
The first aswer here has sources for this https://www.quora.com/Does-6-2-1-2-equal-1-or-9
PEMDAS is the system it’s using. Wierdly I only just realised division and multiplication are reversed vs. the U.K. system.
Latest Answers