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Wednesday, October 20th, 2010
9:51 am - 141% more!


I saw an advert for a printer today that used the slogan “Was kostet 141% mehr Format?” (a bit difficult to translate, since that use of “Format” is not idiomatic for me even in German, but literally “What does 141% more format cost?”).

I only saw it from afar (enough to see the slogan and two pictures of printers), but I presume they were referring to printers that could print on A3 rather than A4 paper.

As you may know, the “A” series of paper sizes (defined in ISO 216 and commonly used in Europe, for example) have side ratios of 1:√2, which means that if you put two sheets next to each other along their long sides, they’ll be the same as the next bigger size of paper. So successive sizes have twice the surface area, and each side is √2 longer than the preceding size.

So “141% more format” is doubly wrong: even though it’s nonsensical to me at face value (I suppose, in printing there might be a jargon use of “format” that I don’t know…), the most obvious interpretation to me is area: but an A3 sheet of paper doesn’t have 141% more area than an A4 sheet: it has twice the area, or 100% more.

And even if they refer to side length: A3 isn’t 141% longer on each side, it’s 41% longer. Alternatively, it’s 141% of the length, but the ad referred to “141% more”.

I’m guessing the confusion arose from the fact that photocopiers in Europe often have predefined zoom values of 141%, 100%, and 71%, where 141% is useful for enlarging A5 to A4 or A4 to A3 (and 71% for the reverse)—so some poor innumerate person took the “141%” number relating A3 to A4 and made a slogan talking about “141% more”.

Which makes as much sense as telling someone who got a 2% pay raise that they are now earning “102% more money than before”.


current mood: annoyed
Math it!
Thursday, March 19th, 2009
9:22 pm - More percentage madness
rabid_chemist Delaware governor Markell is proposing an 8% pay cut for all state employees.

In the comments, there's this gem from Moonrise:

"What about treating married vs single fairly. His plan does not do that. He wants to combine the two pays to say they are rich if their combined pay is $60, 000. That a $30, 000 a year job each. Two singles living together making the same about are considered under under paid. HUH. Another slap to married couples. A family of two state workers married are going to take a double hit on pay deduction, and lose their double share on healt benefit. Shouldn't it be double share it is two workers? Under Mackell this family is losing in the cost of medical plus takes a 16% pay cut. FAIR?"
Math it!
Friday, December 12th, 2008
5:45 am - Oh my
rabid_chemist Via Not Always Right:

You’re Just Compounding The Issue

Text below cutCollapse )

3 math corrections| Math it!
Thursday, August 21st, 2008
7:37 pm - Apparently 95-83 somehow equals 8

2 math corrections| Math it!
Thursday, March 6th, 2008
5:36 pm - Counting to two

Sorry, forgot to cut the picture the first time!

American Apparel adCollapse )

Now I'm not that good at math, but...
5 math corrections| Math it!
Sunday, November 25th, 2007
9:33 pm - not knowing math leads to making people scared


In this article on global warming, the writer makes the claim:

"The number of people affected by extreme natural disasters, meanwhile, has surged by almost 70 percent, from 174 million a year between 1985 to 1994, to 254 million people a year between 1995 to 2004, Oxfam said."

An increase of 70% from a base of 174 million should be 295.8 million. The writer did 174/254 to come up 70% (after a round off). It's actually a 42.6% increase, which is also pretty scary, but they are overstating the problem. However, in a few more years, we're prolly about that screwed.
2 math corrections| Math it!
Tuesday, November 6th, 2007
10:25 am - Adults in the UK don't understand negative numbers
kait_the_great This isn't complicated. This is in the "should be able to understand this to function in the real world" category:

"I phoned Camelot and they fobbed me off with some story that -6 is higher - not lower - than -8 but I'm not having it."


text of articleCollapse )
3 math corrections| Math it!
Wednesday, October 3rd, 2007
3:22 am - ancestry

So this happened some time ago, but I'm new to the community and I thought I should share.

After discussing my lineage with someone, an acquaintance, he commented that he too was part Irish. 1/8th Irish. He then commented that he was 1/3 Jewish.

I spent a great deal of time trying, as much as I could, to explain that this was impossible. He insisted (somehow) that he was in fact, exactly* 1/3 Jewish. I decided that whatever the case was, he was 0/3 good at math.

*added for clarity.

Further clarity:

I just re-read the community info, and it says maybe to provide explanation (I don't know if this counts as "college level"). So if anybody is wondering, no matter what part of your ancestry something is, it must be representable in least terms as k/2^n (for nonnegative integers k,n). The reason is this: at some level of your ancestry, presumably, there is a set of ancestors that are all "100%" something. There must be 2^n of them.* So you count up k of them to be something (eg Jewish), and that means you are k/2^n parts Jewish, by simply summing.

For example, if your father is 100% Italian and your mother is half Italian, half Chinese (with a 100% Italian parent, say her mother), then you skip up to that generation:

father's father: 100% Italian
father's mother: 100% Italian
mother's father: 100% Chinese
mother's mother: 100% Italian

There are 3 full-Italians, and 4 total. You are 3/4 Italian.

*regardless of if some are repeated - eg your grandfather is your mother's father and your father's father, he will essentially function as two distinct grandfathers in the summation, and will contribute two terms of 1/4.

You could also argue this inductively. Assume someone's parents are all k/2^n of anything (for various values of k,n). The child is simply the average of the two. So if the father is k/2^n of X, and the mother is p/2^q, then the child must be:

k/2^n + p/2^q = (k 2^q + p 2^n) / 2^(q+n)

While that is not in least terms, you can at best cancel out more twos. Note that this also accounts for cloning, in the sense that if the child is cloned, the inductive step involves no averaging and becomes trivial.
13 math corrections| Math it!
Monday, July 23rd, 2007
3:55 pm

VH1 has these celebrity specials on TV all of the time. This one was from Rags to Riches talking about Naomi Watts and Nicole Kidman.

Text comes up showing Naomi Watts gets $5 million per picture.

The guy doing the voices informs us that Nicole Kidman gets "almost twice that" and text with $17.5 million comes up.
6 math corrections| Math it!
2:07 am

I'm not mocking anybody, but there was an awful lot of people unashamed to proclaim their inability to do basic math. It was getting a little depressing.

3 math corrections| Math it!
Saturday, July 14th, 2007
1:42 pm - Bizarre Curve-Fitting

There are a lot of problems with this article about tax policy from an economic standpoint. (carnap describes them nicely.) But the worst use of math is the curve in the graph. What the heck is it???

(I saw this in stat_geeks first.)

current mood: confused
3 math corrections| Math it!
Thursday, June 14th, 2007
8:35 am - Good heavens
rabid_chemist Two-month old infant with pneumonia prescribed .2 mL of carbaxafed. Dropper has fractions (1/4 mL, 1/2 mL, 3/4 mL, 1 mL). Confused parents overdose infant with 2 mL.

The news story also points out that carbaxafed isn't approved by the FDA, which is a bit misleading because it was approved at the time of the overdose (1 1/2 years ago). The FDA tightened standards a year ago, and carbaxafed was cut. The parents are also blaming the language barrier, which makes me wonder what "0.2 mL" looks like in Spanish.
5 math corrections| Math it!
Sunday, June 10th, 2007
8:42 am - Wow.

I couldn't think of a good reason why a 23 year old would not know how to measure 2/3 or 3/4 given a 1/3 or 1/4 measure.

Then someone explained it using a pie example, and OP got it, and said that s/he'd never had it explained like that.

My teacher cut up apples to show us fractions in grade 2 (age 7-8). I never thought of my school system as being very competent -- maybe it was only my teachers who rocked.

Off topic discussion of excellent math teachers vs. terrible onesCollapse )
5 math corrections| Math it!
Saturday, February 10th, 2007
11:31 am

I have been had having my students calculate the percentage of correct answers on their homework, first as a fraction, then as a percent. one girl got three out of four right and argued with me that her score should be 90 percent because it was only one less than the total possible. so she could convert between fraction and % when the denominator with 10, but not with any other number.

this was surprising coming from a high school junior, but at least there was some attempt at reasoning.
Math it!
Sunday, December 24th, 2006
7:31 pm - Good going, Captain D's.

I went out to eat tonight, and I ordered cheese sticks with my meal.

"Half order or whole order?" the woman at the register asked. I asked how many cheese sticks came with each order.

"Oh, you get four with a half order and eight with a whole order," she replied.

The kicker? A half order costs $.99, and a whole order costs $2.29. I should have ordered two half orders just for the reaction.

current mood: aggravated
2 math corrections| Math it!
Saturday, December 9th, 2006
8:46 am
kait_the_great Hey,

Number One: I was just ranting in my personal journal about this common mistake I see in communities a lot, so much so that it's turned into a pet peeve:

[ ETA: Here's a transcript of the call: http://verizonmath.blogspot.com/2006/12/transcription-jt.html ]

Number two: I was ranting about it because of this interesting essay on the attitudes surrounding innumeracy in North America. If you don't agree, keep reading to the bottom; there are some well-written rebuttals:


PS: I updated the community profile because it was freakishly long and boring.
2 math corrections| Math it!
Wednesday, November 29th, 2006
10:52 am - Find the next term

2, 3, 5, 7, 11, 13, 17, 19, 23, ...any ideas?Collapse )
6 math corrections| Math it!
Sunday, August 13th, 2006
9:33 pm - John Paulos

hey guys,

this is my first time posting, i'm a junior at temple taking a BS in mathematics. Unfortunately, I don't have any fun innumeracy jokes now, but I do have an amazing prof. who actually wrote a book entitled "Innumeracy" his name is John Allen Paulos.

and he is bascially amazing.

take care
2 math corrections| Math it!
Wednesday, June 21st, 2006
11:01 pm - Oodles of math stupid...

I've taken to collecting innumeracy posts from mock_the_stupid (with permission) to post here (without editing cause otherwise they'll never get posted).


You decide - stupid or scamming?Collapse )


Some very simple arithmeticCollapse )


Fun with non-existant fractionsCollapse )
1 math correction| Math it!
Tuesday, June 20th, 2006
1:54 pm - chem test

The test had about 30 questions. At the top the test said 100 points total 25 points each.
5 math corrections| Math it!
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