Help with mathematic problem solving question.

theoretica wrote: »

Put the digital calculator away and do mental arithmetic.

The most important piece of advice in the whole topic. :T

I have my A level and S level (do those still exist?) maths, and did an engineering degree more than half my lifetime ago; I know that calculators are necessary. For this problem they aren't and just make it more difficult. Knowing when to use the calculator and when not to is a vital skill too.

I'm not one of those that rant about calculators making maths too easy, because people who say that tend to think there is no more to mathematics than arithmetic and long division is as difficult as it gets :rotfl: .

As former maths teacher, I think that, beyond showing a child how useful a calculator can be, they should be banned from use in maths work, until secondary school.


A big problem with calculators is the fact that many people don't realise what type of calculator they are using; basic and scientific ones, working in different ways.


A basic calculator, as found on computers, works the four rules in the order given, whereas a scientific one works according to BODMAS (ie brackets first, then any multiplications and divisions, followed by additions and subtractions)


3X4-2X5


A basic calculator does 3X4=12, 12-2=10, 10X5=50


Whereas the other works 3X4=12, 2X5=10, 12-10=2


This calculation usually intends (3X4)-(2X5), making the second the desired answer.


I agree with the above ie don't use a calculator for fraction questions as the child is required to practice cancelling and conversion between decimal and 'vulgar' fractions often doesn't give an exact answer.

For the 1.8/1.5, the simplest way is to convert this to 18/15. Then to convert this to the simplest fraction you note that both 18 and 15 are divisible by 3, which gives you 6/5.