## Archive for the ‘Math & arithmetic’ Category

November 28, 2017

Yesterday, we posted a question posed to me by my soon-to-be 9 year old granddaughter … and challenged you to give it a try:

Determine the numerical values for a roasted turkey, a slice of pie and a cob of corn.

Here’s the answer … if you haven’t already done the problem, do it before peeking:

### Are you smarter than a 3rd grader?

November 27, 2017

A Thanksgiving Day puzzle from my granddaughter.

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What does your family do for fun at Thanksgiving?

Nowadays, mine tries to stump me with math problems.

This year, my soon-to-be 9 year old granddaughter brought over a set of puzzles that she’d been working on at school (3rd grade).

Give one a try:

Determine the numerical values for a roasted turkey, a slice of pie and a cob of corn.

We all like to whine that American students are slipping behind other countries in math and science … which begs a basic question:

Are you at least as smart as a third grader?

I’ll post the answer tomorrow …

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Thanks to AMH for feeding the lead.
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#HomaFiles

September 25, 2017

Here’s the ANSWER to to last week’s math challenge

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Last week, we touted Chicago’s Noble Network of Charter Schools … specifically, its intensive math curriculum

And, we presented a challenge question (taken from the 10th grade curriculum) …

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Noble Charter HS – Math Challenge Question

The rectangle shown below is divided into four green squares, seven gold squares, four orange squares, and one blue rectangle.

If the perimeter of the blue rectangle is 20 cm, what is the perimeter of the larger rectangle?

Here’s the answer …. and a method for get it.

### Question: Are you smarter than a 10th grader?

September 22, 2017

A math success story … and a challenge (for you).

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Earlier in the week, we posted results of a report ranking U.S. high school students #40 in math literacy among developed nations.

A friend reminded me that those are averages … and there are some bright lights.

One such bright light is shining at Chicago’s Noble Network of Charter Schools.

Noble is comprised of a growing network of high quality public high schools located in Chicago’s communities of greatest need.

Noble has 18 campuses educating 12,000 students.

True to its mission, 98% of the students are minorities and 89% low income.

Here’s the kicker …

According to Stanford’s Center for Research on Education Outcomes:

Students at The Noble Network of Charter Schools receive the equivalent of nearly two years’ worth of math in each single year. Source

What kind of math are they working on?

Here’s a problem from the 10th grade curriculum …. try it.

### Math Trix: The case of the gifted stock-picker…

January 29, 2016

I’ve been reading a book called How Not to Be Wrong: The Power of Mathematical Thinking by Jordan Ellenberg

The author recounts a classic stock advisor scam that goes like this …

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One day, you receive an unsolicited newsletter from an investment advisor, containing a tip that a certain stock is due for a big rise.

A week passes, and just as the Investment advisor predicted, the stock goes up.

The next week, you get a new edition of the newsletter, and this time, the tip is about a stock whose price the adviser thinks is going to fall.

And indeed, the stock craters.

That’s good, but it gets even better …

### Math Trix: The case of the gifted stock-picker…

September 30, 2015

I’ve been reading a book called How Not to Be Wrong: The Power of Mathematical Thinking by Jordan Ellenberg

The author recounts a classic stock advisor scam that goes like this …

======

One day, you receive an unsolicited newsletter from an investment advisor, containing a tip that a certain stock is due for a big rise.

A week passes, and just as the Investment advisor predicted, the stock goes up.

The next week, you get a new edition of the newsletter, and this time, the tip is about a stock whose price the adviser thinks is going to fall.

And indeed, the stock craters.

That’s good, but it gets even better …

### Eureka: Common Core’s new math … take the minute quiz.

September 15, 2015

Heard a story recently about a 3rd grader who was failing math.

Her state had signed up to the Common Core Standards (and testing) … and her school district had embraced the the Common Core curriculum.

When the Fs started coming home, her father – a college-educated engineer – jumped into the fray to tutor her.

The Fs kept coming.

The Fs kept coming  even though her answers were right … her process of arriving at the right answer was wrong.

Before you say, “well, certainly she needs to do the problem the right way”, take this simple test.

Question: Little Joey has a jar with 35 jelly beans.  He gives away 17 of the jelly beans to his friends. How many jelly beans does Joey have left in the jar.  Show each step of your calculation and label all numbers.

Do it !  Should only take a few seconds ….

### Math Trix: The case of the gifted stock-picker…

April 20, 2015

I’ve been reading a book called How Not to Be Wrong: The Power of Mathematical Thinking by Jordan Ellenberg

The author recounts a classic stock advisor scam that goes like this …

======

One day, you receive an unsolicited newsletter from an investment advisor, containing a tip that a certain stock is due for a big rise.

A week passes, and just as the Investment advisor predicted, the stock goes up.

The next week, you get a new edition of the newsletter, and this time, the tip is about a stock whose price the adviser thinks is going to fall.

And indeed, the stock craters.

That’s good, but it gets even better …

### Math Trix: The case of the gifted stock-picker…

August 21, 2014

I’ve been reading a book called How Not to Be Wrong: The Power of Mathematical Thinking by Jordan Ellenberg

The author recounts a classic stock advisor scam that goes like this …

======

One day, you receive an unsolicited newsletter from an investment advisor, containing a tip that a certain stock is due for a big rise.

A week passes, and just as the Investment advisor predicted, the stock goes up.

The next week, you get a new edition of the newsletter, and this time, the tip is about a stock whose price the adviser thinks is going to fall.

And indeed, the stock craters.

That’s good, but it gets even better …

### Quick, pick one: a 33% discount or 33% more for free …

July 17, 2012

According to a study at the University of Minnesota’s Carlson School of Management, report in The Economist

When offered two deals on loose coffee beans: 33% extra free or 33% off the price, most shoppers considered them equivalent though he discount is by far the better proposition … it would take a 50% increase in quantity to be equivalent.

More generally, the researchers found, that shoppers prefer getting something extra for free to getting something cheaper.

For example, the researchers sold 73% more hand lotion when it was offered in a bonus pack than when it carried an equivalent discount (even after all other effects, such as a desire to stockpile, were controlled for).

The main reason is  “consumer innumeracy” … e.g. people can’t do fractions or simple math in their head.

* * * * *
How can retailers compensate for (or exploit) consumers’ math blind spots?

One way is to befuddle them with double discounting.

People are more likely to think that a product that has been reduced by 20%, and then by an additional 25%, is a better deal than one which has been subject to an equivalent, one-off, 40% reduction.

Similarly, when evaluating a car’s fuel efficiency, consumers understand the number of extra miles per gallon it gets, more so than the equivalent percentage fall in fuel consumption.

We’re not talking calculus, we’re talking fractions … ouch.

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