No, actually, we can't. As with most things in math there is only one correct way to do it. And once again, being able to do math with fractions is COMPLETELY unrelated to english/metric units. You can have 1/2 or 1/4 of a meter just as easily as 1/2 or 1/4 of a foot, and the math is done exactly the same way.

Your point is that decimal math is easier than fractional math. I can't agree with that. I suspect you are referring to the fact that you can more easily use a calculator to input 0.500, but you are hard pressed to enter 1/2.

Personally, I can add 3/16 + 1/16 much faster in my head than I can enter 0.1875 and 0.0625 into a calculator.

 

Sorry Chris, but I'm guessing that once you cross the room, you've forgotten why. That's not a math thing. The two-digit number you have trouble remembering is your AGE...

I'm a member of that club, by the way, being more than halfway through my sixth decade. The other two-digit number I have problems with is the number of ex-wives.

 

You go, Joe.

Fractions are not intrinsically difficult or scary. Many of my students (adults; I don't teach K12) find fractions difficult and scary when they first arrive, but except for those students who clearly and obviously rank on the low end of the spectrum, in basically every case I've been able to get information about their fear and anxiety is due to poor experiences in the past.

Once I can get students to move past their emotional issues with fractions, they almost always discover that they are not nearly as horrible as they have always believed.

 

I don't think you need to learn any math these days. Just enter your question into PC and the answer pop right up. Actually soon you won't need to learn anything ,only how to use a computer. I use to remember 20-30 telephone #. Now I can hardly remember my own. I just hit speed dial. However you won't know if the computer is giving you the right answer, just an answer. Personal intelligence is slowly disappearing from humans. Just call a government agency looking for assistance to confirm that fact. They will only tell you what the computer tells them. Right or wrong. I see it almost every day. When the power goes out, we can all stare out the window and wonder what's going on out there, just like my dog.

 

Isn't 1 inch exactly 25.4 mm?
I thought this was decided by the yard and pound agreement of 1959.

 

Jepp I am 92,5 kg.
Give me my weight the British way?(Stones etc.)

 

You are completely correct. In 1959, an international agreement established that 1 inch is exactly 25.4 mm.

 

I have a hard time wrapping my head around the concept of buying pants with a 96 waist. (Insert obese Americans joke here...)

 

Interesting that you mention that because pants sizes are in inches over here too.

 

And of course sheet metal measured in gauge.

A 20 gauge steel sheet and a 20 gauge aluminum sheet does not have the same thickness
if I got it right?

 

The history of metal and wire gauges is complex and related to actual manufacturing realities that prevailed 200 years ago.

An interesting article on the subject is here, from which I excerpt this quote:

"The sequence of the sizes of a gauge is not linear. The sizes of the Birmingham Wire Gauge, measured and published by Holtzapffel [4], are presented in Table 1 and can be approximately expressed by the formula: thickness in inches = 0.300 × 0.897(gauge number–1). This is an exponential decay curve in accordance with the law of decrease by constant proportion. In this formula, 0.300 in. is gauge number 1 and for each successive gauge number the wire is reduced to 89.7% of the preceding gauge number. Why this decrease by constant proportion? The size of the step or reduction for each draw depends on the cohesive strength, or Van der Waal’s forces, in the material, proportional to the cross-sectional area of the wire. The wire breaks when the cohesive strength of the resulting wire equals the cohesive strength that has to be overcome during the reduction."

- Eric

 

To convert kilograms to pounds (lbs) multiply by 2.2046.
2.2046
92.5
110230
440920
20402550
=204.0255

So you weigh 204 lbs if you blow your nose .

To convert lbs to stones (st) divide by 14.
204 lbs divided by 14 = 14st 8lbs.

So you didn't blow your nose?.
Now we want .0255lbs expressed in ounces. 16 ounces = 1lb
Simple, multiply by 16.
.0255 x 16 = .468, just under half an ounce.

Expressed in Imperial terms you weigh; 14st 8lbs and 1/2 an ounce.

If you about 6 feet tall you are probably in reasonable shape.

Roger.

 

I think many years ago one of the states decreed that the value of pi was three.

Defining exactly how long a metre is, or how long a second is, or the precise mass of a kilogram keeps mathematicians and scientists permanently occupied and arguing.

Roger.

 

I love all this stuff. I was lucky to go through the education system when everything was metric, but outside of school my father worked in feet and inches, so I had to learn both.

The only thing that does occasionally catch me out is the conversion decimal-inch to fraction-inch, just takes that extra second or two to work out.

And lets not forget things like fingers, hands, rods, chains, and furlongs as units of distance. Then there is the long ton, short ton and tonne...

Perhaps shall save spellings for another thread... At work I think in English, have to write in American, then throw in a bit of Dutch for good luck

 

I enjoy them all. Different tools that work better for different jobs.
I just did a kitchen.
Measured the room in feet/inches. Close enough.
Measured the cabinets in inches/fractions of an inch. Close enough.
However, when constructing the drawer boxes and doors, I use metric. It is much easier for me to determine if the pieces will be square, if I use millimeters.

It is much easier for me to think "100" than it is to think 3 and 15/16ths and is much easier counting to ten than 16. It ends up being more precise, to boot.

If you're off a 16th of an inch across a span of 20 cabinet doors, that's 20/16" or 1 and 1/4" or 32mm too big or small for the doors.
If you are off 1 mm across the span of 20 doors that's 20 mm or approx. 3/4 of an inch.

Trust me, it makes a big difference when it comes time to adjust the hinges.

 

Ohhhhhhhh... You're THAT guy, eh?

The one where I go to fix something, and the measurements don't seem to add up quite right, and I realize, "OH - he did this part in Metric" after wasting fifteen minutes scratching my head.

- Eric