The 12 Times Table...

[sandyRoe]

I always had trouble with 12x elevens. I'd say to myself 12x tens are 120 and one more 12 is 132.
Why are they being reintroduced into schools?

[Octavius]

My 6 year old comes home from school chanting her times tables.

Sometimes I get the calculator out to see if she's right.

[sandyRoe]

And those of us who drink beer mostly prefere the pint.

[dannyk13]

A tip for multiplying a two figure number by eleven is to add the figures together and insert in middle e.g 11 x 12 = 1 + 2 = 3 inserted between figures = 132

[FredPuli43]

Quite right too, Sandy, and it's still legal to sell draught beer by the pint, therefor. Why we didn't have the same exemption for petrol is not clear; everyone talks of mpg. We still have miles, after all, so we don't use litres per 100 km, and litres per 100 miles, though possible, would never catch on.

[jim360]

I'm sure that's the case, but I don't see that this represents any inherent "betterness" of Imperial over metric. It's just that people in general are more used to Imperial in some situations.

Maths in general is about making things as simple as possible. Metric is simpler to use than Imperial. What's wrong with making life easier for yourself?

[sandyRoe]

I agree. It's just what you're used to. The children being educated now will probably think of the distance to travel in km and the journey in km per hour when they become drivers.

[Octavius]

Fred, simple economics really - and as has been mooted - social class. e are a dual nation, and kids still learn conversion factors.

Pricing petrol in ppl was down to the European petrol pump design, so it was easily transferred and installed across the Europe. You will still get the tabloids talking price per gallon, and the broadsheets talking pence per litre though, perhaps a nod to their demographic.

The cost of converting all UK road signs was in the £800m mark. Car manufacturers put dual systems in cars for speedos. In a German taxi last week I was looking at the speedo doing 165kph and working out what that was in mph.

[sandyRoe]

÷ by 8 and x by 5, ithink

[sandyRoe]

I'm not sure I'd be happy in a taxi going at 100mph.

[Octavius]

102mph

[FredPuli43]

165 kph ? Easy.That's 165 x 5 furlongs, divided by 8 for miles : 103 miles per hour approx! Canada has road signs etc in kilometres, never miles. Their costs may not have been as high as ours would be. Strangely, I find that youngsters, taught metric, still tend to give heights of people in feet and inches. They will say that a man was ten metres away but looked to be about five foot eight. It may be that they don't really know what feet and inches are but know what tall, short, and medium, heights are in imperial and a lot of older people they know still think in imperial for height and use that

[jim360]

km/h rather than kph. Has to be said that the 5 furlongs per kilometre is a new conversion to me but seems wonderfully accurate. I make 5 furlongs = 1006m so that's 99.5% accuracy -- good going by any standards!

One thing I think metric captures better than imperial, though, is scale. once you have learned the meanings of kilo, nano, deci, milli, micro, Mega, Giga, etc., then you have to learn only what a metre, or gramme, or litre, or whatever is and you have virtually all scales of all measurements covered. By contrast each new scale in Imperial is given a different name so you have to learn the relationships separately -- and even then the numbers themselves don't lend themselves to easier visualisation, I think. A yard is to a foot as 3/8 of a mile is to a furlong, and a stone is to a pound as 14/16 pound is to an ounce...

But kilo is to mega as mega is to giga, is to Tera... simpler scaling. For the win.

I still enjoy being able to use and think in and convert between both systems. This has the advantage that I can talk to my grandma and describe something being so many metres long and then convert to yards for her benefit -- or from grams to ounces and pounds whenever my mum needs help with reading a recipe. But I know which system I prefer to think in!

[Octavius]

I grew up in the decimal age and work within metrics, but for some reason I find it easier to visualise things in feet and inches with my measuring eye. I also work on the basis that 1km is around 5/8 of a mile. In the gym (yes I do go!) I weigh myself in stones & pounds then lift kilos!

As I said we are a dual nation always converting and calculating.

[craft1948]

At Junior school we had to learn up to the 16x table.
One of my graduate trainees at work (he had a 1st class degree in electronic engineering) was amazed I could do mental arithmetic....he couldn't at all.

[quinie]

Hi,gness,what was the fingers on the table method for teaching the 9x table?Just interested.

[factor-fiction]

Jim360- thanks for your post at 9:39 on Tuesday. You make some interesting points and I agree with some of them. However in dismissing rote learning of tables I think you are looking at this from your position of being good at maths.

I agree that we need the flexibility to calculate things such as 14 x 15 mentally. But I feel you or I would get to 210 very quickly because we know 14 x 10= 140 and 14 x 5 =70 (or we may do 14 x 1.5 = 21 then multiply by 10).

However someone who hasn't learned tables by rote or learned them in some other way would probably struggle. When I moved from finance into teaching I was shocked at how many students can't do basic calculations- they would be unable to multiply by 10 or work out 4x5. Many would go wrong or give up before getting to the end of the mental process.