## Sometimes, Estimating is Better Than Getting the Exact Answer

People ask me why I keep writing posts about math. Mainly, it’s because I care about critical thinking, and I want students to learn how to think logically. That’s a skill most of us didn’t learn how to do at a young age. And that’s why, when it comes to math, so many people flip out when they see a problem done “the wrong way.” They just assume they know better. Any deviation from traditional methods is heresy.

It’s frustrating for me because I know what the teachers are trying to do, but it’s not always obvious to the parents whose first reaction is to complain on Facebook.

Take this problem that has been shared more than 20,000 times on Facebook since last week:

## Why Would a Math Teacher Punish a Child for Saying 5 x 3 = 15?

What’s 5 x 3?

You might think those are simple questions, but a third grader had points taken off on an exam recently after giving the answers 15 and 24, respectively.

“But those are the right answers,” you say. And a lot of people on Reddit would agree with you.

So what’s going on?

At first glance, the child seems to have done everything right.

## This is How Anti-Abortion Groups Lie with Statistics

Over the past several years, Planned Parenthood has increased the raw number of abortions it provides. In 2006, they performed 289,750 abortions. By 2013, the number had gone up to 327,000. It’s possible the increase is, in part, due to the lack of alternative locations for women to get the procedure done.

Over that same time period, the number of anti-cancer services dropped from 2,007,371 to 935,573. Why the drop? Because for some services, like pap smears, there were “changing medical standards about who should be screened and how often.”

If you’re a pro-life politician who wants to use that information to make Planned Parenthood look evil, what do you do? Easy. You just have to assume your base isn’t intelligent enough to look into the details of whatever you show them. It worked with the recent anti-Planned Parenthood videos, after all.

So yesterday, during a congressional hearing, Rep. Jason Chaffetz (R-UT) showed Planned Parenthood President Cecile Richards this chart documenting those numbers:

## The Dad Who Wrote a Check Using “Common Core” Math Doesn’t Know What He’s Talking About

Doug Herrmann, a father from Ohio, was frustrated that he couldn’t help his second-grade son with his math homework last week. Even though it should have been easy, the curriculum his son was using didn’t look familiar to him. It wasn’t the way Herrmann learned math growing up. On Tuesday, he wrote on Facebook: “Mental math and ten-frame cards? Common core sucks!”

Then, on Wednesday, he posted a check made out to Melridge Elementary School in the amount of… well, no one was sure, because he did it “using common core numbers.”

He didn’t actually send the check to the school, but the post struck a nerve. It’s been shared more than 25,000 times as of this writing and a whole bunch of articles have been written about it. Herrmann is already scheduled to appear on Fox & Friends Wednesday morning.

But does he have a point?

Not at all. Instead of trying to figure out what his child was learning, Herrmann did what so many parents do these days: He complained about something he doesn’t understand.

I’ll be honest with you: I didn’t know what “ten-frame” cards were and I wasn’t sure what he was trying to write in his check. Then I spent a couple of minutes doing the research he couldn’t be bothered to do himself.

So let me back up for a moment and try and explain this. It’ll take a second, but it’ll be worth it, I promise.

## Friendly Atheist Podcast Episode 73: Dr. Keith Devlin, Mathematics Communicator and Author

Our latest podcast guest is Dr. Keith Devlin, a mathematician who’s also known as The Math Guy on NPR’s Weekend Edition. He has written several books explaining math to the masses. And he’s also the co-founder and Executive Director of Stanford University’s Human-Sciences and Technologies Advanced Research Institute (H-Star).

We spoke with Dr. Devlin about why math is difficult to understand and explain, how we tend to know more about mathematicians’ lives than their work, and whether programs like Khan Academy help or hurt students.

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