BIDMAS BODMAS

[MoverOfPaper]

Help!

Argument ragging in my house over Y7 maths homework...

Which is correct?

1.Brackets
2.Indices/Order
3.Dividing
4.Multiplication
5.Adding
6.Subtraction

Or

1.Brackets
2.Indices/order
3.Whichever is furthest right of division or multiplication then work from right to left
4.Whichever is furthest right of addition and subtraction and work from right to left?

DD has been taught both ways at various times (she thinks) by different teachers or teaching assistants.

Thank you anyone. I would call NobleGiraffe but hopefully she is up to her neck in gin and not thinking about school.

If you could also provide an example of how to do it I would be so grateful

the question is;

use operations (+ , - , x , /, () to make 12345*6=44 a true statement.

my notes [/ means division but we can't work out how to get that symbol.]

1.Brackets
2.Indices/Order
3.Dividing/ Multiplication (of equal importance)
4.Adding/Subtraction (of equal importance)

(5 x 5) - (3 / 2) + 2

25-1.5+2 =25.5

The whole point of BODMAS/BIDMAS is that you do it in that order.

5 x 5 - 3 / 2 + 2

The key thing is you have no brackets, so multiplication and/or division take precedence over the addition/subtraction. So start with the stuff that needs multiplied or divided.

That will give you constituent bits for your eventual sum as follows
5 X 5
3/2
2

giving you 25, 1.5, 2 which you then put together thus: 25 - 1.5 + 2

25.5

(or if you prefer to think of it Purple's way, you have
25, -1.5, 2 which have to be added up).

@nicerbeing

The whole point of BODMAS/BIDMAS is that you do it in that order.

But you don’t have to do it strictly in that order. It’s better that the mathematical principles are taught without over reliance on sticking rigidly to the acronym.

It’s better that the mathematical principles are taught without over reliance on sticking rigidly to the acronym.

True...

Though I'm starting to have traumatic flashbacks to my first year undergrad mathematical logic course and Polish notation and operator scope .

en.wikipedia.org/wiki/Polish_notation

Don't think I ever quite understood it. I mean, I sort of got what it was about conceptually, but actually using it in anger? Hell, no!

Still don’t understand if the multiplication and division takes order precedence over addition and subtraction in a sum like the one below

6 - 2 + 4 x 5 / 2 + 9

Would that mean that according to the bidmas/bodmas rules (two names for same thing ..... it’s super easy kids) would mean

Order of events for sum
6 - 2 + 4 x 5 / 2 + 9

4 x 5 first
Then divide that by 2
Then do the first bit 6 - 2
Then finally + 9

Please can somebody really spell it out this system like I’m a kid as it’s not going in

6 - 2 + 4 x 5 / 2 + 9

First multiplication & division

4 x 5 / 2 you can do as either 4x5=20 divided by 2 = 10 or 5/2 = 2.5 then 4 times that which miraculously still = 10

So now we have 6 - 2 + 10 + 9

you can do that in any order you like eg
6 add 10 add 9 makes 25, subtract 2 makes 23

or 6 subtract 2 makes 4 add 10 makes 14 add 9 makes 23

or negative 2 add 10 makes 8, add 6 makes 14 add 9 makes 23

BUT you must make sure that negative sign sticks tightly to the 2
6 - 2 + 10 + 9 What you must not do is say 2 add 10 add 9 makes 21, so 6 subtract 21 is negative 15.

The - sign means negative 2, it doesn't mean subtract everything that comes to the right of it until you get to the end.
ie it is ABSOLUTELY NOT 6 - (2+10+9)

6 - 2 + 4 x 5 / 2 + 9

Brackets first: There are none.
Order second: There are none.
Multiplication or Division third: There are both.

4 X 5 / 2. You can choose whether to do:
(4x5)÷2 which is 20÷2 = 10
Or
4 x (5÷2) which is 4x2.5 = 10

Once you've done that, you can rewrite your sum: 6 - 2 + 10 + 9

Now you only have Addition and Subtraction to do. As it doesn't matter which order, you can either add all the positive numbers together (25) and subtract 2, making 23, or do the sum in order 6 - 2 (4) + 10 (14) + 9 = 23.

I “think” we understand now. I think the problem was being taught a set of rules rather than being taught the concept, the why. When the rules changed ( different teacher) panic and anxiety set in.
We have now got homework to do!
Thank you all!