One of the hardest things to get used to about living in Ireland has been adjusting to the metric system. Learning the metric system requires a complete rewiring of the old grey matter and I just don't know if the dendrites are up to forming new pathways. I think it's much more difficult to learn a system of measurements when you already know one because you don't think of the new measurements in relation to themselves, you think of them in the context of the system you already know.
I've developed a series of approximations and bizarre quasi-formulas that helps me get by, for the most part.
Kilometers to Miles
I'm a runner, so this one is a bit easier for me to wrap my head around. I've done loads of 5-kilometer runs and know that the distance is around 3.1 miles. So, to get from kilometers to miles, I multiply by 3 and divide by 5. For example, what does 12 kilometers equal in miles?
(12 * 3) / 5 = 7.2
Check my work. And remember, I said these were approximate. I'm trying to figure out how far I have to run or how close the grocery store is - I'm not doing chemistry experiments or brain surgery. Close enough is good enough for my puposes.
Celsius to Fahernheit
I have dim memories of this one from high school. I know it involved the fraction 5/9 but I don't remember how. I also know that I found it scary. But then, I found most math scary in high school and that's why I'm a writer and not a veterinarian.
My cheat for C to F is to take the temperature in Celsius, double it and add it to 30. It gets me close although the pattern doesn't hold for temperatures much past 90.
(Which is okay because it just doesn't get that hot here.)
Let's look at a couple of examples:
12 C = 24 + 30 = 54 --> 53.6, so essentially 54.
3 C = 6 + 30 = 36 --> 37.4, in the ball park.
25 C = 50 + 28 = 86 --> 82.4, close enough for government work, I think.
40 C = 80 + 30 = 110 --> This is where my cheat totally breaks down. My father-in-law recently had a temperature of 40 C. I did my quick mental math and thought that it had to be wrong. Sure enough, 40 C is around 104 F.
You can find a great temperature converter here.
Kilograms to Pounds
This is a toughie for me. I think it's because it defies my brain's attempt to force comparisions and logic on this strange new world. It seems to me like if it takes more kilometers to make a mile, then it should take more kilograms to make a pound. It's just a mental block sort of thing because when you think about it, I shouldn't have this expectation at all. One group measures distance, the other measures weight - it's beyond apples and oranges territory and right into pineapples and kumquats. But this is just the way my mind thinks.
My dad told me his sister's tried and true formula to get from kilograms to pounds, which was "Take half and then subtract a little." I try to reverse it - double it and add a little.
I'd guess the following:
55 kg = 125 pounds --> It's actually 121.
100 kg = 220 pounds --> And in fact, it's 220.46.
17 kg = 34 pounds --> It's actually 37.47.
To check my work (or your own wild guesses), go to google and do a search like:
55 kilograms into pounds. The first result it returns is the exact answer. Cool, huh?
Stones to Pounds
You're probably thinking "stone, that doesn't sound very familiar or very metric-y to me." And you would be right on both counts. Stone is an arcane imperial measurement that has somehow weathered the tests of time in Ireland and the UK, especially in regard to the weight of people. It's not uncommon to tell someone what you weigh in pounds and to have them say "What is that in stone?"
A stone is 14 pounds, which is a damn awkward number to multiple if you don't happen to be Rainman, which I most definitely am not. And forget about dividing by 14. Luckily, I am not in the habit of announcing my weight to people, so I haven't really come up with a Pound to Stone conversion formula.
I do have occasion to go from Stone to Pound though,so I do a bit of math trickery. Say you weigh 15 stone. That's 15 * 14, which just about gives me brain freeze. So I think of it as
(10 * 15) + (4 * 15) = 150 + 60 = 210
This will bring to an end Ann's Messed-Up Approximate Math Class for today. Ounces and liters, pints and liters - that all eludes me. Maybe because they still (and I hope always will) serve Guinness by the pint.