Wednesday, 23 March 2016

Mathematical stuff.

Further to my rant about grammar, style, call it what you will, and children having to learn grammatical terminology, here's another little conundrum. 

When we were in school, sometimes in Maths we were set "problems". These were Maths questions in words, designed to make us apply to supposedly real life situations the theory we had learned using numbers. It included things like average speed of boys on bicycles and who would arrive first at the destination and stuff like that. 

Now, my daughter is currently teaching a class of eight to nine-year-olds and she was telling us about a new super-whizz method of teaching them Maths. Some of this includes ... wait for it .... problems. She and her husband, both intelligent and well qualified, not behind the door in mathematical ability, were having some difficulty understanding how the solution to a particular problem had been reached. So she threw it at Phil and me. 

It went like this: 

"A man saves £3500 in the first six months of the year. His pay for sixth months is double the amount he spends. In the second sixth months of the year he spends £4200 more than he saves. How much does he save in the second six months?" 

This is where I am supposed to say, "If you want to work it out for yourself, don't look at the answer below". 

I quickly worked out the correct answer according to the text book. But my intelligent daughter, her intelligent husband and my intelligent husband could not see how I arrived at that answer. 

All three had done stage 1: 

If the man's pay for six months is double the amount he saves in that first six month period, then he earns £7000 for sixth months work. Check - all good. 

and stage 2: To determine how much he saved in the second sixth months, you first need to subtract what he spent from the total earned: £7000 - £4200. Answer: £2800. Check - all good. 

And then they got stuck. So I told them that stage 3 was this: 

Divide that £2800 by 2, giving two lots of £1400. One of these he spent, making his total spending £5600 and his saving £1400 

How did I know that? That is what they demanded. They simply could not see what looked absolutely logical to me. And because it was so obvious, I was hard put to explain it. And it niggled at me until I wrote it down as follows and emailed it to them: 

An attempt at explanation: 

Amount earned = £7000 

Amount saved unknown = x 

Amount spent = x + 4200 

Amount saved (x) + amount spent (4200) = amount earned (7000) 

x + 4200 + x = 7000 
x + x = 7000 - 4200 = 2800 
2x = 2800 
x = 2800 divided by 2 = 1400 
Answer : 
he saved £1400. 

My point is that if three intelligent adults had difficulty getting their heads round the problem, how does anyone expect eight-year-olds to do so? And why should eight-year-olds be having to think about what people earn and spend and save? Where does that come into their experience of the world? 

Has education gone crazy?

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