"Pheww it's 90 today" or "Pheww it's 32 today"?

[si404]

than the assortment of digits in the latter!

There's just as many different numbers to add in the former as the latter: 1234568 (missing 7 and 9) vs 1234578 (missing 6 and 9).

[decimal points are] how you deal with non-whole numbers in pretty much every other domain

Fractions don't exist?

 

[Domh245]

There's just as many different numbers to add in the former as the latter: 1234568 (missing 7 and 9) vs 1234578 (missing 6 and 9).

Sure, but for me at least it's a lot easier to just work in multiples of 5 (and 10) than it is to do the maths 'properly'. Adding 40 to a number is a lot easier than adding 8, 85 (as 5+80) is easier than 17, etc

 

[si404]

Adding 40 to a number is a lot easier than adding 8

Why is adding 4 to the tens column any easier than adding 8 to the units? That makes no sense!

Same for 8 in the tens column vs 1, and 5 in the units rather than 7...

 

[mmh]

What matters is not the English words, but that you'd making currency-arithmetic more complicated.

I don't think you're making it more complicated. Making it different, sure. I'd argue simpler for everyday mental arithmetic, as you're no longer working with large numbers by default, even to do small value calculations. Many people struggle with a sum like 70+52 or 134-79. Twenty is less daunting to deal with.

Look at the expression £0.15 - that's the same as 15p - so conversion is easy and follows exactly the same rules for decimal points that you would use for ordinary numbers.

But there's no conversion there, you've not actually demonstrated anything, just shown that there are two notations. I know that the 15p is 15% of 100p and is therefore 0.15 of a £, but of itself that's of little use, and less in day to day mental arithmetic. It also lends itself well to a form of maths teaching which I don't think helps anyone - fixating over percentages and moving the magical decimal point around. It's not a particularly helpful way of looking at things for the numerate, and I suspect it does far more harm than good when the innumerate are just baffled by it.

But if you're using £'s and shillings, what does £0.15 mean? Normal rules of arithmetic would say it means 0.15 of a £ which would presumably be 3 shillings. But surely you'd want to write 3 shillings at £0.03, not as £0.15, wouldn't you?

I wouldn't suggest writing a non-decimal figure in decimal notation, no. Why would you want to? Where does that leading padding zero come from?

It will very quickly get very confusing. Or to take another example, how do you convert 75 shillings to £'s? If it was 75p, it would be trivial - just move the decimal point to make £0.75. But if you're working in shillings with 20 shilllings to the £, you have to actually do a calculation to convert.

There's that magical decimal point. You're talking about moving it with an example where it didn't exist, and if it had it wouldn't have needed moving. Your example isn't equivalent in a decimal system - in one the value is less than a pound, in the other it is over. The equivalent would be 75 shillings vs. 375p. In one I need to know there are 20 in a pound, the other 100 in the pound. In day to day mental arithmetic you wouldn't start from 75 shillings, the shillings would have been converted to pounds as they reached 20. The same actually happens in decimal, but we pretend it doesn't because the notation allows easy representation of numbers far too large to be comfortable with.

Of course all of those problems can be solved. You could invent a new convention for representing shillings, and you could get people to learn the calculations. But you're still making things needlessly hard, when working in units of £ and £/100 is so much easier.

All you need is to multiply and divide by twenty, which is no harder than multiplying or dividing by 100. If it were commonly taught in schools teachers would probably come up with a magical property to make it suitably confusing. No need to come up with a new notation, we've already got an ancient one which would do just fine.

 

[Domh245]

Why is adding 4 to the tens column any easier than adding 8 to the units? That makes no sense!

Same for 8 in the tens column vs 1, and 5 in the units rather than 7...

Beats me as to why exactly I find it easier, but I do! If I had to guess, it's down to carrying numbers over more consistently in the 'units' - either nothing carries over and it's as simple as adding the 10s, or carrying over 10 if both numbers end in a 5. Carrying over is less of an issue when dealing with 10s/100s as it happens less frequently

 

[AM9]

Beats me as to why exactly I find it easier, but I do! If I had to guess, it's down to carrying numbers over more consistently in the 'units' - either nothing carries over and it's as simple as adding the 10s, or carrying over 10 if both numbers end in a 5. Carrying over is less of an issue when dealing with 10s/100s as it happens less frequently

Those arguing for regressing to non-decimal currency are sounding like Europhobes on steroids. I used £sd until I was over 20 years old and quite frankly it was a real time waster. Within hours, after 15th February 1971, I found £p to be as simple as counting plain numbers, (something that most of the world including the lands that formed the UK, had been doing so for over 800 years). The UK has been counting miles, feet, pounds, gallons, acres and almost anything else in decimal. So the fact that it was bits of metal with various monarchs heads stamped on them doesn't change the way we count. Decimal units are here to stay on practically everything except time between one second and one year (because of the way the components of the solar system interacts), and Nautical Miles which although it has a geometric relationship with the size of the earth, is really only still used because the US dominated most things involving air transport and it would be too complex to change it all now.

 

[xotGD]

Actually, metric time would be good. 100 seconds in a minute. 100 minutes in an hour. 10 hours in a day. 10 days in a week (with a 3 day weekend!).

It breaks down after that. If only we could speed up the earth so a year was 100 days!

 

[si404]

Actually, metric time would be good. 100 seconds in a minute. 100 minutes in an hour. 10 hours in a day. 10 days in a week (with a 3 day weekend!).

It breaks down after that. If only we could speed up the earth so a year was 100 days!

It was so terrible to actually live that the French Revolutionaries went back to 24 hour day of 60 minutes after about a year of mandatory use. And it's not like they dropped it because they had waned in their love of ten: the bill that overturned the mandatory use of decimal time was the same one that mandated use of the metric system!

The calendar had a bit more success, but the 10 day week was got rid of due to unpopularity a couple of years before the calendar ended at the start of year XIII. Maybe the calendar failed because it used Roman numerals for the year or because it had 12 months, and so didn't praise 10 enough...

 

[mmh]

I am surprised that nobody has criticised the Gas Mark in this thread yet...

 

[xotGD]

I am surprised that nobody has criticised the Gas Mark in this thread yet...

Also known as 'Regulo'.

 

[RichT54]

I'm currently fitting a fancy new German made tap to the basin in the bathroom. It needs an adapter - OK, fair enough. But the German end is documented as 3/8in and the UK end is 15mm - what's that all about?