MHB Order Of Ops: 6-1x0+2÷2=7: Debunking the Myth

[Rachel1]

6 - 1 × 0 + 2 ÷ 2 =
Hi :) I was hoping someone could explain this equation? Using PEMDAS the answer came to 5 for me but I have been told the correct answer is 7? Why is this?

 

[Rachel1]

Re: Simple equation help

I'm not sure why the multiply sign is showing as a different symbol...

 

[MarkFL]

Re: Simple equation help

Hello and welcom to MHB, Rachel! (Wave)

I've moved your thread here, because our Challenge Questions and Puzzles forum is for presenting problems to the community as a challenge to solve.

I believe your expression is:

$$6-1\times0+2\div2=$$?

First, we carry out the multiplication and division from left to right:

$$6-0+1=$$?

Now we carry out the addition/subtraction from left to right to obtain:

$$7$$

Does that make sense?

 

[Rachel1]

Re: Simple equation help

Thank you!

 

[Rachel1]

Re: Simple equation help

When using PEMDAS it states that addition comes before subtraction.
Why is it that the 0 + 1 is not done first and then finally the 6 - 1 ?
That's the part that confuses me lol

 

[MarkFL]

Re: Simple equation help

When using PEMDAS it states that addition comes before subtraction.
Why is it that the 0 + 1 is not done first and then finally the 6 - 1 ?
That's the part that confuses me lol

Addition and subtraction are at the same level, and are done from left to right. Subtraction is really just the addition of a negative number, much like division is just multiplication by the reciprocal (multiplicative inverse). :D

So, in an expression like you posted, where there are no bracketing symbols (parentheses, etc.) and no exponents, we first do the multiplication/division from let to right, then we do the addition/subtraction from left to right. Multiplication and division have the same precedence as do addition and subtraction. :D

 

[Rachel1]

Re: Simple equation help

Oh ok cool, that makes sense.Thank you so much for explaining!