Most of us have seen posts such as this on social media; did we really waste those maths lessons trying to find x and y?
It might surprise you to know that we use algebra quite a lot in ‘real’ life.
Here’s just one example:
This requires knowledge of algebraic formulae. (Sounds brainy, doesn’t it?)
It simply means that, if your turkey is 5kg, you need to work out that the cooking time will be 20 minutes multiplied by 5, then add on another 90 minutes.
In algebra (where ‘c’ is the cooking time and ‘w’ is the weight of the turkey) this would be expressed as c = 20w + 90
Of course, we don’t actually say that when we’re working out how long we need to cook the turkey (well, most of us don’t) but we’re doing exactly the same thing.
And how about when you book a taxi, or pay an engineer to fix your boiler?
Most taxi firms will charge you a standard rate for a call out, plus so much per mile or kilometre.
Boiler engineers usually charge a call-out fee, then so much per hour of their labour, plus parts and VAT.
Recently, I asked my Twitter followers which aspects of the maths they learned at school do they use regularly in adult life (and which they don’t). I wasn’t surprised by the number of responses claiming never to have needed algebra, but I was pleasantly surprised to receive the following from Hannah at Daisy Media:
Not being a knitter myself (I tried it once but my attempt finished up hanging from a tree in my garden, where I’d thrown it) I wasn’t convinced, so had a look at some knitting patterns online. And Hannah’s right: knitting is one of the most mathematically challenging tasks you can try. Who’d have thought it?
Yes, mum – really: you are an algebra whizz!
There are so many more areas of adult life in which algebra is used – some related to certain occupations, some to hobbies, and others to domestic tasks.
Time to look at some of the weird and wonderful stuff your child’s being taught at school that you’re sure you never needed to know:
1 Number Lines
Certainly in
Key Stage 1, children seem to use number lines for everything – adding, taking
away, multiplying and dividing. And it doesn’t help that there’s more than one
kind of number line, and seemingly countless ways they can be used.
It’s worth getting familiar with number lines; they really help children understand what happens to numbers when they’re learning new types of calculation.
Division is just one of the many ways in which number lines are useful
2 Partitioning
You probably have vague memories of learning about Hundreds, Tens and Units, but you’re sure you didn’t have to break every number down into those place values before adding, or whatever calculation you’d been asked to do.
Why can’t
your kids just be taught to put it all in a column, like you did? Much quicker.
Partitioning
is really useful when children are getting used to bigger numbers, especially when
learning how numbers behave when different kinds of calculation are applied.
It’s particularly helpful with mental maths if you understand how each digit is
affected by its place value, and it helps with other methods, such as the grid
method for multiplication.
Speaking of
which …
3 Grid Method (Gridding)
The grid
method is particularly helpful for children learning to multiply numbers that
are bigger than those they would learn off by heart.
Yes, it takes longer than the traditional long multiplication method, but it does help children (and adults) understand what’s happening within the more formal multiplication methods. A good stepping-stone from informal methods to the more formal method.
The Grid method is a great stepping stone from number lines to the more formal column method for multiplication
4 Chunking
What?
Chunking is
a term used in some calculations, such as division, whereby several pieces of
information are ‘chunked’ together to make one easy-to-remember piece of
information, thus speeding up the calculation process.
For example,
when children are learning to use repeated subtraction to understand division:
85 ÷ 5
How many lots of 5 do we need to take away from 85 until there are no 5s left?
Rather than
taking away one lot of 5 at a time, they can start by taking away one big
‘chunk’ of 5s:
85 take away ten lots of 5 that’s 85 – 50
which leaves 35
So now you’re left with 35, which is 7 lots of 5
How many lots of 5 in total did you need to take away?
10 lots of 5 add 7 lots of five = 17 lots of 5 There are 17 lots of 5 in 85
So 85 ÷ 5 = 17
5 Multiplying and Dividing by 10, 100 and 1,000
‘Surely you just bung a zero on the end when you multiply by 10?’
That works
until you have to multiply a decimal number by 10.
1.5 with a
zero on the end gives you 1.50, which is the same as 1.5
And what
about dividing by 10 when your number doesn’t have a zero on the end to knock
off?
Knowing
which way to move the digits depending on whether the number is being
multiplied or divided, and knowing how many places to move those digits
depending on whether the number is being multiplied or divided by 10, 100 or
1,000, really helps children understand how our base-ten number system works.
And it’s a huge help when they start learning decimals!
Learning what happens to the digits when we multiply or divide by 10, 100 and 1000 helps with much more complex calculations, such as when we use decimals.
Even though some of the methods your child uses to solve calculations may seem strange to you – even a waste of time – be assured that they are useful for understanding how numbers and calculations work.
