Jack’s Common Core Subtraction Problem: Not So Hard After All

DISCLAIMER:  I have no children in public school nor am I a public school teacher. That said, I am no fan of Common Core (and especially not of its implementation).  I find it unfortunate, however, that people are so quick to point out how bad certain Common Core math problems are without looking at what the correct answer should actually be.  Take, for example, this math problem which has been in the news lately: common core subtraction I know this will be hard, but let’s assume for a moment that you don’t know much about subtraction and especially don’t know about things like borrowing (at least that’s what we used to call it back in the day).  While the above problem does NOT require borrowing, it’s setting us up to be able to understand how borrowing will eventually work. So what did Jack do wrong?  The goal here was to start with the first number (427), then count backwards on the number line using each place of the smaller number (316) from largest to smallest (i.e. from the hundreds place to the ones place).  Jack started by going from 427 to 327 to 227 to 127, so he expertly handled the hundreds.  Next, he needed to account for the tens place.  This is what he missed.  He should have gone from 127 to 117.  Finally, he should account for the ones place by going from 117 to 116 to 115 to 114 to 113 to 112 to 111. Why is this kind of reasoning important?  Remember, we don’t know anything about “borrowing.”  Now, instead of subtracting 316 from 427, let’s say we want to subtract 327 from 416 (416 – 327 = ?).  Using the exact same method: Go down by three hundreds – 416 to 316 to 216 to 116 Go down by two tens – 116 to 106 to 96 Go down by seven ones – 96 to 95 to 94 to 93 to 92 to 91 to 90 to 89 So without having to grasp the abstract concept of borrowing, we find that 416 – 327 = 89. Again, I’m no public school teacher, but having taught arithmetic, pre-algebra, algebra, statistics and pre-calculus at the post-secondary level, I can tell you that it’s definitely easier to get student buy-in to abstract notions like carrying and borrowing when they have demonstrated for themselves using the number line that these shortcuts do, in fact, give the correct answer. It’s OK to dislike Common Core, but you only look ignorant when you call out problems like the one above without addressing what the correct solution is and how you think the concept should be taught differently.

Everyone Has A’s! A’s! A’s! A’s!

This past semester, I took an undergraduate course for the first time in nearly 20 years.  I enrolled in Physical Anthropology (ANTH 102) at San Diego City College as the first step toward my goal of becoming a nautical archaeologist.  I didn’t know what to expect, but I certainly didn’t expect such a lax grading policy for a class that qualifies as one of only two science courses required to earn a bachelor’s degree in California.

A total of 600 points were possible for the class.  300 of those came from three projects, each of which took about four hours to complete.  The first project required a visit to the San Diego Museum of Man (mine is here).  The second required online research of various primates or a trip to the San Diego Zoo (click here for my zoo project).  The final “creativity” project was a presentation of literally anything having to do with anthropology (my project is here).  One student baked cookies and wrote various vocabulary words on them.  Another held up a picture book of Disney’s Tarzan and talked about how much he enjoyed reading it to his son.  From what I could tell (based on a quick glance at the professor’s grade spreadsheet when she was showing me my own scores), grading for these projects was binary; students either received 100/100 points for turning them in or 0/100 points for not turning them in.

The other 300 points were based on the best three of four multiple choice tests.  There was no final exam.  Additionally, 25 extra credit points were awarded for attendance at a one-day anthropology conference and, when test scores were abysmally low, another 25 points were awarded for writing a one-page review of any movie having anything to do with anthropology (one student wrote about Ice Age).

This grading policy meant that by simply completing the three projects, students already had 300/600 points (350/600 if they did both extra credit “assignments”).  In order to get a C in the class, a student who did both extra credit assignments would only need an additional 70 points from all three tests.  That’s an average grade on each test of 23.3%!

You read that correctly.  My classmates could get credit for one of their two required science classes by answering less than one-quarter of the multiple choice test questions correctly.

Here’s how it breaks down with and without extra credit for each grade:

Average test score needed to get a(n):    A          B          C

With no extra credit assignments:          80         60        40

With one extra credit assignment:          71.7      51.7      31.7

With both extra credit assignments:        63.3      43.3      23.3

That’s right.  Students who completed both extra credit assignments could score an average of 63.3% (barely a D) on their three highest tests (remember, the lowest score was dropped) and still get an A in this science class.

America, you have been warned.  This is your future.

But for now, everyone has A’s! A’s! A’s! A’s!

Noah’s Flood – Probably Real, Probably Caused By Climate Change, and Probably NOT Due To Anthropogenic Global Warming

Last month, I noticed several articles mocking Republican Congressman Joe Barton for citing the Biblical “Great Flood” as an example of climate change not caused by man:

“I would point out that people like me who support hydrocarbon development don’t deny that climate is changing,” he added. “I think you can have an honest difference of opinion of what’s causing that change without automatically being either all in that’s all because of mankind or it’s all just natural. I think there’s a divergence of evidence.”

“I would point out that if you’re a believer in the Bible, one would have to say the Great Flood is an example of climate change and that certainly wasn’t because mankind had overdeveloped hydrocarbon energy.”

Notice especially some of the comments from “Top Commenters” who mock Congressman Barton:

Oh yeah and to hell with what all those stupid scientists have learned through their years and years of extensive research, those idiots don’t know nothin’. YAY JESUS! -Dave Fox


Thanks for sharing Tim….I feel much dumber now for having read that….LOL.  What a douche! -Patrick Salyard


RUBE. -Lawrence Edward Martin

What many of those commenters (and perhaps even Congressman Barton) don’t know is that the Great Flood story is not unique to the Bible.  The most similar flood story appears in the Epic of Gilgamesh, with Utnapishtim taking the same role as Noah.  Encouraged by the ubiquity of the flood myth, geologists William Ryan and Walter Pittman hypothesized that such a flood actually occurred.  They concluded it was due to the bursting of a natural dam in the Bosporus around 5600 B.C. as sea level rose in the Mediterranean (sea levels were rising as global temperatures rose and continental ice sheets melted).   In 1997, they published the book Noah’s Flood, which not only looked at the similarities between the biblical story of Noah and the tale of Utnapishtim, but also looked at information like genetic data, geologic samples and the language diaspora away from the Black Sea to support their theory.

But does the fact that two geologists from Columbia University wrote a book supporting the idea that the flood actually happened mean Congressman Barton is not, in fact, a “douche” and a “rube” when it comes to anthropogenic global warming?  Perhaps William Ryan and Walter Pittman are also douches and rubes.  If that is the case, their douchiness and rubery is quite advanced; this past December, Robert Ballard (the same Robert Ballard who found the Titanic) started looking for evidence of the settlements which should have once existed around the fresh water lake at what is now the deepest part of the Black Sea (if Ryan and Pittman are correct).  His initial survey did not find anything, but he plans on returning this summer.  It would seem, at least for the moment, that science has come down in support of Congressman Barton.  Earth’s climate is capable of changing of its own accord, even catastrophically.  Sometimes those changes are so catastrophic they take on an epic (one might even be tempted to say “biblical”) quality in the retelling.

Safety and Rumors

By now I am used to receiving emails from my son’s school with spelling and grammar errors as well as factually incorrect information, but this one was just downright confounding for its utter lack of substance:

Subject:  Safety and Rumors

Good evening, this is a message from [school name redacted] High Administration.

We are contacting you about a number of rumors that have been circulating among our students about something bad happening on our campus. We can assure that these are all rumors. Our school police have followed up on all leads that have come to us and have found nothing credible. You and your children are safe here at [name redacted] High School and we will continue to follow up on any information that comes to us. We have a vacation just around the corner and we expect to see everyone here tomorrow. Thank you.

After reading it, I was more worried than if I had never gotten an email to begin with.  What rumors?  I hadn’t heard any rumors.  My son hadn’t heard any rumors.  What’s going on?  Then I remembered… Fleetwood Mac is playing in Anaheim tonight.  Given their track record, the school probably just forgot the “u” in Rumours.

Ferris Bueller Is Doctor Who

Versions of the Doctor

My kid “proved” this to me while we were stopped at a traffic light:

Ferris Bueller was portrayed in the film Ferris Bueller’s Day Off by Matthew Broderick.

Matthew Broderick voices Simba as an adult in Disney’s The Lion King.

The Lion King is a retelling of Shakespeare’s Hamlet (with Simba as Hamlet).

Hamlet was portrayed both on stage and on screen by David Tennant.

David Tennant took on the role of the Tenth Doctor in 2005.


Doctor Who Singing Twist and Shout: