## Reblog: Putting Bill Gates in Proportion

[Feature photo above by Baluart.net.]

Seven years ago, one of my math club students was preparing for a speech contest. His mother emailed me to check some figures, which led to a couple of blog posts on solving proportion problems.

I hope you enjoy this “Throw-back Thursday” blast from the Let’s Play Math! blog archives:

## Putting Bill Gates in Proportion

A friend gave me permission to turn our email discussion into an article…

Can you help us figure out how to figure out this problem? I think we have all the information we need, but I’m not sure:

The average household income in the United States is \$60,000/year. And a man’s annual income is \$56 billion. Is there a way to figure out what this man’s value of \$1mil is, compared to the person who earns \$60,000/year? In other words, I would like to say — \$1,000,000 to us is like 10 cents to Bill Gates.

When I looked up Bill Gates at Wikipedia, I found out that \$56 billion is his net worth, not his income. His salary is \$966,667. Even assuming he has significant investment income, as he surely does, that is still a difference of several orders of magnitude.

But I didn’t research the details before answering my email — and besides, it is a lot more fun to play with the really big numbers. Therefore, the following discussion will assume my friend’s data are accurate…

## Bill Gates Proportions II

Another look at the Bill Gates proportion… Even though I couldn’t find any data on his real income, I did discover that the median American family’s net worth was \$93,100 in 2004 (most of that is home equity) and that the figure has gone up a bit since then. This gives me another chance to play around with proportions.

So I wrote a sample problem for my Advanced Math Monsters workshop at the APACHE homeschool conference:

The median American family has a net worth of about \$100 thousand. Bill Gates has a net worth of \$56 billion. If Average Jane Homeschooler spends \$100 in the vendor hall, what would be the equivalent expense for Gates?

## Can You Read the Flu Map?

[Map as of early afternoon on May 4th, found at the NY Times.]

Compare the dark circles (confirmed cases) for Mexico, New York and Nova Scotia in the top part, or Mexico and the U.S. in the lower part of the map. It’s easy to see which has more cases of the flu — but how many more? Which would you guess is the closest estimate:

Mexico : New York : Nova Scotia

• = 7:3:2 or 20:5:3 or 16:2:1?

U.S. : Mexico

• = 1:2 or 2:5 or 3:7?

## Historical Tidbits: The Pharaoh’s Treasure

[Read the story of the pharaoh’s treasure here: Part 1, Part 2, and Part 3.]

I confess: I lied — or rather, I helped to propagate a legend. Scholars tell us that the Egyptian rope stretchers did not use a 3-4-5 triangle for right-angled corners. They say it is a myth, like the corny old story of George Washington and the cherry tree, which bounces from one storyteller to the next — as I got it from a book I bought as a library discard.

None of the Egyptian papyri that have been found show any indication that the Egyptians knew of the Pythagorean Theorem, one of the great theorems of mathematics, which is the basis for the 3-4-5 triangle. Unless a real archaeologist finds a rope like Alexandria Jones discovered in my story, or a papyrus describing how to use one, we must assume the 3-4-5 rope triangle is an unfounded rumor.

## Bill Gates Proportions II

[Feature photo above by Remy Steinegger via Wikimedia Commons (CC BY 2.0).]

Another look at the Bill Gates proportion… Even though I couldn’t find any data on his real income, I did discover that the median American family’s net worth was \$93,100 in 2004 (most of that is home equity) and that the figure has gone up a bit since then. This gives me another chance to play around with proportions.

So I wrote a sample problem for my Advanced Math Monsters workshop at the APACHE homeschool conference:

The median American family has a net worth of about \$100 thousand. Bill Gates has a net worth of \$56 billion. If Average Jane Homeschooler spends \$100 in the vendor hall, what would be the equivalent expense for Gates?

## Putting Bill Gates in Proportion

[Feature photo above by Baluart.net.]

A friend gave me permission to turn our email discussion into an article…

Can you help us figure out how to figure out this problem? I think we have all the information we need, but I’m not sure:

The average household income in the United States is \$60,000/year. And a man’s annual income is \$56 billion. Is there a way to figure out what this man’s value of \$1mil is, compared to the person who earns \$60,000/year? In other words, I would like to say — \$1,000,000 to us is like 10 cents to Bill Gates.

## Percents: Key Concepts and Connections

[Rescued from my old blog.]

Paraphrased from a homeschool math discussion forum:

“I am really struggling with percents right now, and feel I am in way over my head!”

Percents are one of the math monsters, the toughest topics of elementary and junior high school arithmetic. Here are a few tips to help you understand and teach percents.