11 Plus Exams Forum

18 - (9-5) x 3 = ?

To my mind there should be another set of brackets either round the 18 and the ) or the ( and the 3 - otherwise there are two possible answers surely ?

Thoughts ?

I think you would need to use the BODMAS operation for this (Brackets,Of,Division,Multiplication,Addition, Subtraction).
It has be be done in that order to get the right answer. Stand to be corrected if I am wrong

I'd have expected BIDMAS to apply, so brackets, then multiplication and finally subtraction.

Oh ok, so there are rules then ?

Well that does make sense, brackets first is 4, then multiplication making it 12, then subtraction from 18 gives the supposed right answer of 6.

Better make sure my son knows this for the future !

Thanks both

Ask him if he's heard of Bidmas or bodmas, I was scornfully told "Of course mum, I'm not stupid!" Some time ago. But I had never heard of it myself.

I remember being taught "Bless my dear Aunt Sally" ... does that work or should the D be before the M?

D before M, so

Bless Dear Messy Aunt Sally?

Bless Dad's Miserable Aunt Sally?

D and M can be in either order as can A and S.

BIDMAS

Brackets
Indices (powers)
Division
Multiplication
Addition
Subtraction

Or across the Atlantic - PEMDAS
Parentheses
Exponents
Mult
Div
Add
Subtract

I like Bless my dear Aunt Sally!

Oh I am glad that M and D can be either way round!

can stick to the Blessing my dear Aunt Sally.... learnt from an unforgettable maths teacher