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Why don't we use the math we learn in school?

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Re: Why don't we use the math we learn in school?

#111

Post by foxes »

alexashka wrote: post #37
rland wrote: post #8

Math is incredibly useful; probably everyone here knows that. But it's actually fine that most people don't use it. What we really need is for every student to realize why math is useful -- so that if they want to, they can go learn it so that they can make some kind of technological contribution to the world. The fact is, you need to be good at math to make some new fundamental breakthroughs in technology. Those bre…

> Math is incredibly useful For what? It isn't useful for teenagers who are trying to get laid and be cool, at all . It also isn't useful for what 99% of humans end up doing, unless by math you mean basic arithmetic, enough to add and subtract on your 'smart' phone. Math isn't useful. People who are amazing at math and are interested in it - they can be useful, but mostly not. What they don't teach in school is how t…

The way the world and universe actually works seems to be described by maths you probably have no hope of understanding with that attitude.

Re: Why don't we use the math we learn in school?

#112

Post by eternityforest »

mulmen wrote: post #75
eternityforest wrote: post #42

People don't use math because... it's only useful if you actually really know it. "Useful" to me means "Lets you do something you couldn't before with a phone". Aside from imperial inch fractions(Not a fan of those!), most things require fairly little understanding of fundamentals. Because most people aren't in tech jobs where they can use it. I don't have a checkbook or do my own investing. I'm single, and very litt…

When you say “imperial system” you almost certainly mean US Customary Units. These are not the same system. The United States has never used the Imperial System. Also, US Customary Units have been defined in terms of SI units since 1893. Personally I don’t find multiplying by two any harder than multiplying by 10. https://en.m.wikipedia.org/wiki/United_States_customary_unit... https://en.m.wikipedia.org/wiki/Mendenha…

Multiplying by all numbers is equally easy or hard with calculators, the problem is fractions break UIs.

Try adding 3/16 plus 1/2. On a calculator that is three separate operations, and if the output is decimal, you have to convert back to a fraction.

And when automated systems convert to fractions, the amount of error is not obvious. With decimals, the computer just adds more digits unless you limit it to a certain number of places. It is safe to add a few extra because you can ignore them.

With fractions the whole point is smallish integers. If a computer says 3/8 inch I have no idea if it's really 3/8 or if its 11/32 and the computer rounded.

It can't just always show the value in 128ths of an inch because... nobody knows what those are and rulers aren't marked that way. So to have a computer display fractions means understand how it does so, it's not obvious(Unless you displayed explicit error values, which would be pretty great)

The whole thing came from a time when very skilled humans with no tech did everything themselves and seems optimized for that at the expense of everything else.

Decimals way easier for applications where all the math is 100% done by the CAD program.

Re: Why don't we use the math we learn in school?

#113

Post by eternityforest »

aardvark179 wrote: post #67
eternityforest wrote: post #42

People don't use math because... it's only useful if you actually really know it. "Useful" to me means "Lets you do something you couldn't before with a phone". Aside from imperial inch fractions(Not a fan of those!), most things require fairly little understanding of fundamentals. Because most people aren't in tech jobs where they can use it. I don't have a checkbook or do my own investing. I'm single, and very litt…

> FreeCAD does geometry FreeCAD can do geometry, but if you can’t reason your way through the constraints you need to set for it to do that then you’ll be flailing around. FreeCAD definitely saves me from doing arithmetic, but not from doing maths.

I usually find the constraints are a pretty direct translation of how I would describe a part in non-tech nical writing.

Math definitely is helpful, but unless you are a full time MechE, it's not like you need to be able to pass a high school geometry class to be able to print a replacement part for something.

Re: Why don't we use the math we learn in school?

#114

Post by tharkun__ »

Broken_Hippo wrote: post #45
paulpauper wrote: post #24

Earlier quoted context omitted.

>What we really need is for every student to realize why math is useful -- so that if they want to, they can go learn it so that they can make some kind of technological contribution to the world. That is what word problems try to instill.

Poorly. Many word problems I had were't actually reflective of real world, everyday living. You know, the sort of things folks working a minimum wage job might encounter. I find it absolutely amazing that we haven't done this better since it has been an issue for literally decades.

I doubt even the "real world" ones will make much impression or sense for kids of that age.

The farmer Bob example for the fence? Definitely real world. Minimum wage farm hand might not be the one doing the buying of fencing material that's true. 10 year old kid learning that math? Doesn't care one bit about fences, even if you make it "Your family has a dog and you just moved into a new house and there's no fence ..."

Minimum wage framing crew helper. You forgot your square. Definitely real world. But you got your tape measure. Use Pythagoras to figure out if your wall is going to be square. Does the minimum wage framing guy care when he's an 11 year old kid? Nope!

Figure out how high your school building is with math and without going to the roof and a loooong "tape measure"? That was cool! Especially since we actually went outside and did it.

Also, and this isn't math but at least science related: gasoline fumes are flammable. Very. Real world. Minimum wage lawn mowing crew guy might want to remember. Loved the presentation our chemistry teacher did. Put some gasoline into a small can and tried to light it. Nothing happens. Had to pour it back out. Next step: let us calculate exactly how much gasoline we'd have to put in for the fumes to be ignitable. Then he did just that, lit it and man that was a nice explosion and flying can!

Re: Why don't we use the math we learn in school?

#116

Post by wanderer_ »

temp8964 wrote: post #49

There’s a sickness in today’s American/western culture related to learning / education: against practice. Teachers design all sorts of activities to facilitate student learning, but they are disgusted to do the most important thing for early learners: repetitive practice. When students start to learn algebra, many of them can’t even do two digits addition/subtraction by hand. Not to mention to do calculations in the…

Then again, those who are more naturally proficient, like myself, were often left to do 30 problems as homework on a topic that they could have done without even attending class that day.

Re: Why don't we use the math we learn in school?

#117

Post by mlyle »

graycat wrote: post #110
mlyle wrote: post #29

Earlier quoted context omitted.

> Uh, there is a carpenter with a Web site that uses the "3, 4, 5 rule", of course, the Pythagorean theorem. Knowing a triplet ain't employing Pythagorean theorem. > [lots of following examples that are moderately deep applied math used in lots of skilled professions] Most people don't do this kind of work or analysis.

> Knowing a triplet ain't employing Pythagorean theorem. 3^2 + 4^2 = 5^2 = 25 guarantees that the angle between the side length 3 and the side of length 4 is a right angle which is what the carpenter very much wanted to know. E.g., the sides might be 30 feet, 40 feet and 50 feet, e.g., for the foundation of a house, and presto, bingo the carpenter knows that the 30 foot side and the 40 foot side form a right angle, a…

Yup, and knowing that having triangle sides multiples of 3,4,5 guarantees that it's a right triangle is not the same as employing pythagorean theorem. You know one triplet, and not why it works, or that e.g. it works for 5, 12, and 13 and 11,60, 61 as well.

A whole lot of people know that measuring a bookcase corner to corner is a good way to square it up, too. But they may not be masters of geometry beyond knowing a rule of thumb.

Re: Why don't we use the math we learn in school?

#118

Post by alexashka »

waynesonfire wrote: post #109
alexashka wrote: post #108

Earlier quoted context omitted.

Yup, humans have been struggling for millions of years. Then math finally came to the rescue.

That's exactly right. "It is a great profession. There is the satisfaction of watching a figment of the imagination emerge through the aid of science to a plan on paper. Then it moves to realization in stone or metal or energy. Then it brings jobs and homes to men. Then it elevates the standards of living and adds to the comforts of life. That is the engineer's high privilege." - Herbert Hoover

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Re: Why don't we use the math we learn in school?

#119

Post by addicted »

The answer to a lot of the reasons why people don’t use math in real life (especially the kind of problems posed in the OP) is because people don’t learn mental math.

You’re not walking around with a calculator or a pen and paper all the time. You will use math in your day to day life if you can do the math in your head.

We need to spend a lot more time in schools teaching children how to do math entirely in their heads. Not only will this apply far more directly to how they would use it in the future, it will also help them understand mathematical concepts a lot better.

Re: Why don't we use the math we learn in school?

#120

Post by jfengel »

eternityforest wrote: post #54
jfengel wrote: post #34

My answer: because most of the math we learn in school is useless. I see a lot of math homework questions on Quora, because students copypaste their homework all the time: What is log (3x +2)- log2 =1? How do you prove that X^2-3 is irrational? What are the roots of the equation x4−4x3+6x2−4x+4=0? When on earth are you ever going to use any of that? The word problems are no better. In a group of 20 adults, 4 out of 7…

Maybe they should get engineers to teach math courses the way they wish they had been taught them, rather than math people who sometimes still seem to think we will be doing this without a calculator?

Engineers have specialty interests. I'd just as soon have it taught by a home economics department, or at worst an MBA. Things everyone should be able to do: read a bill, allocate a budget, estimate how much food to buy for 2 people versus 10 people, plan for retirement, maybe convert a recipe from metric to imperial units. Perhaps get a shop teacher.

Let the future STEM majors learn the rest in their classes. It takes a long time for a lot of that stuff to pay off, and much of it remains irrelevant.

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