Don't understand why double negative isn't used here?

For some of you I'm sure this question is so stupid.
6y-2y-2y =2y

But! You have a double negative (-2 -2) so shouldn't that become an addition i.e =10y

Thanks

Reply 1

chavvo

7

Original post by Disappointed6

For some of you I'm sure this question is so stupid.
6y-2y-2y =2y

But! You have a double negative (-2 -2) so shouldn't that become an addition i.e =10y

Thanks

you don't have a double negative there!

A double negative would be something like 6y - ( -2y) (brackets inserted for emphasis) i.e. "6y minus minus-2" - the two negatives combine to form a positive i,e, 6y + 2y.

Your expression is read as "6y minus 2y minus 2y" - imagine starting with 6 apples, then subtracting 2 apples, then subtracting two apples again. There is no double negative, rather there are two negatives ("subtractions") being performed in succession :smile:

(edited 1 month ago)

Reply 2

Disappointed6

OP

4

Thanks for your reply

I am still not sure because there is a similar question and that becomes an addition.
Also if I put into the calculator -2-2 = -4. So in this case I am getting a double negative.
Maybe I'm just being stupid but this seems to brake the rules

Thanks 👍

Reply 3

chavvo

7

Original post by Disappointed6

Thanks for your reply

I am still not sure because there is a similar question and that becomes an addition.
Also if I put into the calculator -2-2 = -4. So in this case I am getting a double negative.
Maybe I'm just being stupid but this seems to brake the rules

Thanks 👍

-2 -2 means "start with the number 'minus 2' (or 'negative 2' as some people prefer to say) and subtract 2 from it, which results in the number -4 (read as "minus 4" [or "negative 4" if you prefer]). There is no "double negative" here either - simply one number subtracted from another.

Personally, I'm not very fond of phrases like "double negative" or "two negatives make a positive" because the English language isn't as precise as we'd like it to be, and can easily be misinterpreted!

Can you post your "similar question" for comparison?

Reply 4

olygilly

2

Original post by Disappointed6

Thanks for your reply

I am still not sure because there is a similar question and that becomes an addition.
Also if I put into the calculator -2-2 = -4. So in this case I am getting a double negative.
Maybe I'm just being stupid but this seems to brake the rules

Thanks 👍

no, you are not. Use brackets (-2)+(-2) = -4
(6y) + (-2y)+(-2y) = (6y)+(-4y) = 2y

Reply 5

Disappointed6

OP

4

Thanks everyone for your replies. I think I've got it now
What you're saying makes Perfect Sense after plotting it out on a line etc

Someone just showed me just brake it up into equations of no more than two figures.
i.e
+6y-2y = +4
+4y -2y = +2
i.e 2

(edited 1 month ago)

Reply 6

chavvo

7

Original post by Disappointed6

Thanks everyone for your replies. I think I've got it now
What you're saying makes Perfect Sense after plotting it out on a line etc

Someone just showed me just brake it up into equations of no more than two figures.
i.e
+6y-2y = +4
+4y -2y = +2
i.e 2

yes, if you don't have any higher priority operations (multiplication / division / brackets) to worry about, if you just have an expression consisting of a succession of additions and subtractions, then you just read from left to right applying the operations in sequence (you can even apply the operations in any order if you're careful, because a "subtraction" is just an addition [of a negative quantity] in disguise).

So in your case, you start with 6y (or "6 apples" if you prefer something tangible!), subtract 2y ("2 apples") to get 4y ("4 apples"), then subtract 2y ("2 apples") from that intermediate result to leave a final result of 2y ("2 apples").

N,B. don't lose your y's if you're doing algebra: +6y -2y = +4y, not +4 :smile:

Reply 7

olygilly

2

Original post by Disappointed6

Thanks everyone for your replies. I think I've got it now
What you're saying makes Perfect Sense after plotting it out on a line etc

Someone just showed me just brake it up into equations of no more than two figures.
i.e
+6y-2y = +4
+4y -2y = +2
i.e 2

You forgot the y. It should be 4y amd 2y

Don't understand why double negative isn't used here?

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