The Permanent, Unmistakable Mark Human Beings Have Left on Planet Earth

Have we entered a new geologic era, the Anthropocene? Or put differently: hundreds of thousands of years from now, when future geologists sift the earth for clues about our present day, what lasting evidence of our existence will they find? Scientific American presents a rather fascinating article about how we are fundamentally making our mark on the planet. (Spoiler: it involves concrete, plastic, and radioactive isotopes … Continue reading The Permanent, Unmistakable Mark Human Beings Have Left on Planet Earth

A Stradivarius Recovered

Heard a beautiful story on NPR this morning from legal correspondent Nina Totenberg about her late father’s stolen Stradivarius violin. Nina Totenberg manages to make court proceedings compelling for radio. Given the inherent intrigue, music, and mystery in this story, she really produced a beautiful report. Read more and hear the story on the NPR website: A Rarity Reclaimed: Stolen Stradivarius Recovered After 35 Years Continue reading A Stradivarius Recovered

Cheryl’s Birthday Problem and Information Filtering

I love seeing teasers about math and logic gain popular appeal! Here’s the math (specifically, logic) problem that the internet is talking about today:

Cheryl's birthday problem

You can get the full problem nicely presented on either The Guardian or The New York Times websites. A number of other sites are talking about it today, too. Just Google “Cheryl birthday problem.”

I spent some time with the problem and put together this response here. I know that various online outlets have discussed the answer as well; here are the respective solutions presented by The Guardian and The New York Times (don’t click those links until you think about the problem for yourself). But I think there’s a useful “information” framework to use in considering how to arrive at the answer. I discuss that framework at the end.

Spoiler alert — I’m going to discuss the birthday answer starting in the next paragraph.

Continue reading “Cheryl’s Birthday Problem and Information Filtering”

How much do you need to make in LA to afford the average apartment?

Answer: $33/hour, at least And a home? According to a new report from KPCC: The median home price in Los Angeles is $570,500, according to the real estate website, Trulia.com. But consider that the median income in Los Angeles is about half that: $49,497, according to census numbers from 2009-2013. So it’s no surprise that Los Angeles has been rated as the most unaffordable city to rent … Continue reading How much do you need to make in LA to afford the average apartment?

Meet Zequals, a mental math tool

Can some simple rounding help us be more accurate and confident with mental math? The man behind this symbol proposes just that: And it turns out it’s fairly accurate: Basically, using some simplification of numbers we can do mental multiplication more accurately (generally). Confused by the squiggles and colors? Don’t be intimidated. Read more: Zequals: the new symbol that will make us all better at sums | … Continue reading Meet Zequals, a mental math tool