I'm so glad I can do sums without a calculator - Page 2

Q Classic · June 17, 2003, 04:37

still a student. no matter what school i went to, i was always prohibited from using a calculator on tests, and ostensibly on homework.

thus, i can do all arithmetic by hand, a good deal of calculus by hand, a bit of graphing by hand, and memorized some basic constants.

Q Classic · June 17, 2003, 04:39

as for change in round numbers...

as for me, i always liked having a dime, rather than a nickel and two pennies.

Az · June 17, 2003, 04:41

Quote:

and ostensibly on homework.

Luckily, noone is perv enough here to contemplate THAT.

CerberusIV · June 17, 2003, 05:15

Back in the good old days when I was at school calculators hadn't been invented so we couldn't use them. (Actually, it was a fairly awful time but todays kids must not be allowed to think they have it easy

) When the first kid in my class came to school with a calculator it pulled the kind of crowd that you would have to turn up in a Ferrari accompanied by a supermodel to draw today.

It can be almost painful to shop around here. Some of the kids take ages to count the money you give them, then they enter the total on the till and it tells them how much change to give. Then they slowly count it out. Aaaargh!

Does anyone remember using those excercise books at school that had conversion tables on the back showing how many chains there are in a furlong and stuff like that you have never needed to use.

FrustratedPoet · June 17, 2003, 06:07

I was better at mental arithmatic when I was 10 years old than I am now, but I'm still much better than 90% of the people I know.

My school was particularly good on this point, though. They had a system of getting the kids to do multiplication tests (all you need to know for good mental arithmatic) against the clock. They started out pretty easy for the younger kids like having to do the whole 3-times table in 10 minutes, then they got progressively harder by mixing up the numbers, giving you more to do and less time to do it in. The series of tests culminated in the mother of all arithmatic tests where we had to one thousand random sums in 30 minutes (that's less than 2 seconds per question - and no I didn't use a calculator to work it out

).
You would expected educated adults to be able to do that (although many can't), but that's pretty good for 10 year olds I think. It was so funny, we were like little machines just churning out the answers automatically.

No thinking was required - it was all instinctive by that stage.

It's no coincidence that when they moved up to the local Secondary School at ages 11/12 the kids who attended my Primary School were always better at Maths than all the other kids. The effect levelled off a bit as the maths got more complicated later, of course, but it was a great way to give us good grounding in the basics of arithmatic.

Brainwashing is the best way to educate children. Get them to do the sums a million times and they might just get it eventually.

Immortal Wombat · June 17, 2003, 06:20

Quote:

Originally posted by Alexander's Horse
yeah - I don't think there's anything clever about being able to do primary school level sums any more than you do - except fo the fact that a surprising number of people cannot do them.

People are stupid.

FP: at my school I managed 100 in about two minutes I think, when I was 12. It works very well.

Adagio · June 17, 2003, 06:40

There's only two ways I can calculate things:

1) By having a pen and paper close by
2) By using a calculator

The problem is not, that I can't see things through in my head, but my memory is the problem... I've got the worst memory ever... Even after repeating the same sentence 5000 times, withing short time, I still can't remember it... and that's a short sentance...

Dauphin · June 17, 2003, 06:53

Quote:

Originally posted by Alexander's Horse
I'm really glad I was educated before calculators and computers came on the scene. I can do sums in my head or with a pencil - add, subtract, multiply, divide. I know all the basic tricks for mental arithmetic like rounding to 10 and dropping zeros.

I was always good at mental arithmatic from a young age. I learnt a lot of tricks without realising they were tricks.

For example I could work out 29 x 31 = 899 quicker than most people could type it into a calculator. How?

31x29 = (30 +1) * (30 -1) = 30² - 1 = 3² *10*10 -1 =899.

Each step very simple in the mind and far faster than the traditional taught method. There are loads of similar tricks that can leave people astounded at how you calculate things so quickly.

CerberusIV · June 17, 2003, 07:05

Once you can remember all the multiplication tables it is fairly easy to just break larger numbers down.

Example 16*27

16=2*8 and 27=3*9

From memory 8*9=72(I still remember 35 years later)

3*72=210+6=216

2*216=432

so 16*27=432 and it is a lot quicker to think it than type it out.

Dr. A. Cula · June 17, 2003, 07:28

Looking back at my childhood, I realised I had it quite easy, even if I learned all elementary maths before I actually saw a calculator: my mom's basic profession is maths teacher, and my dad is a railroad cosntruction engineer, so, between the 2 of them they worked out a way to teach me how to do mental calculations even before going to school. Though it must be something in the way the brain works, because the same method failed on my sister.

Rufus T. Firefly · June 17, 2003, 07:31

Couldn't agree more, AH; my wife and I face the same uphill battle with our daughter. In her case, it was made worse by the fact that she hates rote work, so crucial aspects of math (like multiplication tables) sent her into fits; I don't think she fully had them down until she was 11, whereas I remember being taught them (and knowing them) at 7 or 8.

Another part of what held her back, though, was how little her teachers expected of her. In the States, with her abyssmal math skills, she was nevertheless an "A" student. But when we moved overseas and enrolled her in an international school with lots of European kids, she found that she knew less than everyone else her age -- and didn't like that feeling one bit. She kicked herself into gear and (many a tearful Daddy/Daughter tutorial later) learned what she needed to. So, as with so many things, I blame America.

rah · June 17, 2003, 08:54

Rufus, I'm sorry your daughter went to such a crappy school. But I'm sure you blame countries for all your own personal shortcomings.

My daughter was required to memorize the multiplication tables early in school, and they were not allowed to use calculators until they had demonstrated mastery. She has consistently gotten "A"s in math. Remembering back to my youth, (I was heavy into math preparing for an engineering school) she is learning things 12 -18 months earlier than I learned them. I was and still am quite impressed with her math schooling. She is not in a special school.

RAH
And who remembers slide rulers.

Az · June 17, 2003, 08:59

Quote:

She is not in a special school.

what do you mean by that?

Asher · June 17, 2003, 09:01

My uni banned calculators as well in any of the non-engineering maths.

Az · June 17, 2003, 09:07

This is a good time to thank France.

France has funded (and founded ) the University of Nice, who has the single webpage that will help me pass the Calc 2 Course aka Hell.

http://wims.unice.fr/~wims/en_tool~a...ction.en.phtml

Thanks France! I love France!

CerberusIV · June 17, 2003, 09:14

I recently completed a degree in earth sciences (geology related subjects mostly) with the Open University. No calculators allowed although all that the courses required was arithmetic, basic algebra and complex numbers.

Yes, I remember using a slide rule - and largely giving up on it because it was quicker to do work it out in my head.

I haven't seen a slide rule in years but one odd item I discovered tucked away in a corner of the office when I started my present job looks like a slide rule but is specifically for calculating volumes of concrete. By adjusting it for the thickness, length and width, it gives the volume of concrete required. One of my predecessors must have been a civil engineer.

rah · June 17, 2003, 09:16

Quote:

Originally posted by Azazel

Quote:

She is not in a special school.

what do you mean by that?

Not in a private school. Just a regular American Public school. Silly.

Urban Ranger · June 17, 2003, 10:54

Quote:

Originally posted by Azazel
France has funded (and founded ) the University of Nice, who has the single webpage that will help me pass the Calc 2 Course aka Hell.

You whuz, that's the easy stuff.

Az · June 17, 2003, 10:56

Thank goodness I don't have to go further ( Well, ODE, and PDE, but I am doing them this simester as well, and they're ok.

)

Urban Ranger · June 17, 2003, 11:05

What kind of engineer are you?

Az · June 17, 2003, 11:40

No kind of engineer. I am a chemist in training.

Solver · June 17, 2003, 16:22

Interesting. Here, calculators are banned till high schools (where, obviously, many calculations DO require those), so everyone is required to memorize the multiplication tables.

I'm not sure, but I think I learnt them myself when I was 6 or 7 - took me long, provided that I could do many other things by then. Oh, and learning how to divide on paper was a pain for me... even more so for my father to teach.

Kuciwalker · June 17, 2003, 17:47

I break it down slightly differently from how Cerberus does.

In his example, 16*27, I would do a sort of long mulitplication in my head.

16*20 = 160*2 = 320
add 7*10 = 70 and 7*6 = 42
432

raghar · June 17, 2003, 18:16

So try this 4/3*(thirdSQRT(513/11*523/19*11/57))*log(4436634>>1)

Without calculator of course and at least on 19 decimals, please.

Provost Harrison · June 17, 2003, 18:16

I had this today when someone was using a calculator to work out some simple averages but before they were getting the numbers into the calculator I had already reeled off the answer...I think this divide occurs at a younger age than I am at fortunately yet I know the power of a calculator for trickier mathematics...the best of both worlds...

Urban Ranger · June 17, 2003, 23:46

What are you, some kind of masochist?

ravagon · June 18, 2003, 00:09

Quote:

Originally posted by Alexander's Horse
I was trying the explain some shortcuts to one of my kids when I was helping him with his homework and he just burst into tears - it wasn't the way he was being taught. He didn't seem to have a concrete idea about numbers in his head the way I do, even when I said stuff like "if you have 6 apples and take away 2, what do you have left?". I had to draw the damn apples!

I think you may have better luck if you lose the apples. Kids don't 'get' apples. Try jellybeans instead and use props.

Urban Ranger · June 18, 2003, 00:39

Or ice cream cones

Sikander · June 18, 2003, 02:39

I'm also good at doing arithmatic in my head. I think wargames are a large part of the reason. Anyone who has gone through one combat phase in DNO should have a firm handle on addition and division for instance.

A friend of mine ran a RP game which was extremely complex. He's got a PhD in Physical Chemistry, and had more math by the time he was a freshman in high school than I have ever had. Anyway, the enormous complexity of his game meant that he needed to constantly use his calulator to figure out things for the game. It bugged him that I could always get the answer faster in my head than he could on the calculator.

June 18, 2003, 12:08

Im very fast at arithmetic also.
Im in math, but as somebody mentionned, that has almost no bearing.
I know ppl with math degrees who take out calculators to add up 2 digit numbers.
I can do quick exact artihmetic (multiplying 2 digits numbers very quickly and such) but maybe from my science background, I can do also rather precise approximations for more complicated stuff, you know converting twice , then multiplying by price and dividing by number of people to estimate what I owe to someone or such. As such, I think this second skill is more useful in day to day life than exact low-level arithmetic, because you can know If something is being charged too much or something like that.