Money makes the maths go down...
Money can make the maths go down, to coin a phrase.
Since Britain’s currency was decimalised many of us have had their first introductions to base ten maths and decimal concepts in money.
Most children are likely to have got a basic grasp of the notion of pennies and pounds, and how they relate, from an early age. And children are likely to have understood this long before they are required by national curricula to have understood tenths, hundredths, performing operations on decimal numbers, and the like.
If nothing else, this proves that if there is a need and a daily context in which to learn, we can acquire complex skills without really realising. But it also gives us a useful tool when tackling calculating with decimal places.
Take the question “3.6 divided by 12″.
It sounds pretty tough to the unconfident. After all, 12 is larger than 3.6, which means the answer will be smaller than one, a decimal value.
Now take the question “£3.60 split amongst twelve people”.
Does the question seem easier? Suddenly it’s about a dozen students going Dutch on an order of poppadoms (substitute scenario as appropriate!).
As soon as we add a pound sign in front of a decimal value in a calculation, it can seem easier to visualise, to handle.
0.01 is one hundredth, an abstract concept. Whereas £0.01 is a penny – it’s solid, and there’s a hundred of them in a pound – easy!
If you struggle with decimal calculations, it might just help to shove a pound sign in front of the numbers, turn 0.4 into £0.40 or 40p, etc. One of the commonest pitfalls of multiplying or dividing with decimals is the failure to show the answer in the right order of magnitude.
For instance, taking 3.6/12, we could make the question easier by writing it 36/12 – the answer is 3. But now what do we do to find the answer to 3.6/12? This can stump people, but using the context of money means that we know £3.6 is 36 10p coins, or 360 pennies.
If the answer to 36/12 is 3, that means three 10p coins, or 30p! And how do we write 30p in pounds? £0.30. Easy! We’ve just converted the whole-number answer to our simplified calculation back into the final decimal answer.
This Maths-Whizz tip comes courtesy of Hilary Koll and Steve Mills, the esteemed and award-winning maths boffins who designed all our Maths-Whizz lesson concepts, people to whom even the God of Whizz tugs his forelock.