Translator: Yifat Adler Reviewer: Denise RQ
Hi, everyone.
I'm Laura Overdeck and today, we are going to talk about
how our fear of numbers in society trips us up
in the most ordinary ways every day.
Before we start, just a couple of quick questions.
How long do you think the stripes are? The dashes in a road stripe on a road?
They have a standard size.
Most people guess they are two or three feet.
They're actually ten feet long.
And the gaps between them are 30 feet, about double the length of your car.
How about highway signs?
How big do you think that little interstate shield is?
It's always the same. It's about 3 feet tall.
It's probably about half as tall as you are.
These things are much bigger than we think
because thanks to speed and distance,
they don't look the way they should,
and you're going to find out what size they are,
only if you go and look up the numbers.
And what's interesting is,
even if we do know the numbers, sometimes we totally blow it.
Look at what we do to Alaska.
You know, it's always shoved in the corner.
If you map Alaska to the same scale as the US, this is what it looks like.
It's huge.
Now, the fact that Alaska is a couple of thousand miles wide,
doesn't really affect us day to day, unless you happen to live in Alaska.
But the road stripes do, because we clearly don't really know
how far we are from the car in front of us when it slams on the brakes.
And it turns out that that lack of awareness of numbers
pervades all kinds of actions we take and decisions we make every day.
The problem is that math in our society is not really a popular subject, right?
It is seen as a dry, tedious subject that you study in school,
and when you leave the classroom you think:
"Oh, I'm never going to have to use that again."
But the fact is, we see in the news that technology jobs are going begging
looking for people with the right skills, and we depend on that.
These are the innovators who are going to develop cheap, clean fuel
or new medicines, or all the other things that we take for granted in our lives.
So that's bad enough.
But I would argue we have a bigger problem,
which is that everybody on the street needs to know how to do math.
Just to live daily life, to be able to know what's happening to you,
and how you make a good decision, how your decisions will have an impact.
And we're not talking about complicated math, this is street math.
This is just understanding numbers and powers of ten and proportion.
The problem is just like not having street smarts,
if you don't do the street math,
you can really go down some bad blind alleys.
And as a society, collectively, if we bumble long not doing the numbers,
we can really go off the rails on a couple of things
as we're going to see.
Now, thankfully the math is easy,
so hopefully these are things we can turn around.
So let's start by looking at how things pile up.
Turns out there's something you do every day for a certain number of minutes.
If you multiply that by six,
that tells you how many hours a year you do it.
So if you play video games 40 minutes a day,
that doesn't sound so bad, right?
But that's 240 hours a year.
That's a week and a half of your life, basically achieving nothing every year.
And tasks we do add up that way too.
So, if you wash your face morning and night,
and you take a towel and rub to dry your eyes a couple of times,
that's 1,800 times a year that you are pulling on your eyes,
and your crow's feet, and the bags under your eyes.
You don't want to do that, right?
When you do the math, you start to see how things pile up.
And what is the math here? It's just multiplying,
which is the same as adding the same number over and over.
Things add up, and as they add up, they start racking up zeros.
Making one bad choice as a one off is not so bad.
But if you make that choice daily,
in three months you've done it almost a hundred times.
In a year, that's a third of a thousand. It really starts to rack up.
What makes the numbers get really big,
is when you multiplied that out not just for you, but for everybody around you.
So, when you are sitting in a traffic jam
- because the road construction next to you isn't done,
and they're not really hurrying up finishing it -
it's not just your time that's racking up,
it's all the people pumping through that highway every day.
Day after day, week after week. We see this all the time.
Jury selection.
There're over 3,000 county court houses around the country,
all of them with people sitting for hours, mostly waiting not to be picked.
Or the DMV, right?
The DMV makes you come, check in, and then sometimes sit for an hour,
before you can finish your five minutes transaction.
This is nothing short of sadism, right? This is 50 shades of the DMV.
(Laughter)
And, you know, there's no pleasure in it. This is painful.
You know, there's no ticker in the sky,
adding up everybody's hours to see what really is the impact
of making us all wait not producing anything.
The reason that we instinctively know this is bad
is because time is money, everyone's time is worth something.
If you have a job, the market has put a value on that.
If you're a family member caring for child or an aging parent,
you're producing something, there's a value.
Volunteers have value. Everybody's time is worth something.
So, every time you use your time, that's a cost.
So, if you drive a couple of miles out of your way to get cheaper gas.
Let's say it's 20 cents cheaper a gallon.
So, if you fill a whole tank,
that's going to come to a few dollars, and that's good.
The question is, is that a good decision?
People might say: "Well, you use a little gas getting there."
That fraction of a gallon is not the swing vote here.
The swing vote is the value of your time.
Because if you take 10 minutes out of your way to do this,
at federal minimum wage that's a $1.20.
Now, if you're not working, and you have no opportunity cost,
this might be a good decision
because there isn't much cost with your time.
But if you're working, you worth at least that,
and if you make more, your time is worth more.
If you make 60,000 dollars a year, those 10 minutes shake out to be 5 bucks.
It might not be worth it.
And the more you make, the more out of balance it's going to be,
and the better the deal has to be to make it worth it.
So, the point is every time you make decisions where you use time,
there's always a cost aligned with the benefit.
So, when you pick up something instead of paying to have it delivered,
or you hunt through the Internet
or through your junk mail and look for coupons,
or on a bigger scale,
if you take on a home improvement project instead of hiring professionals to do it,
in every one of those cases, your time is costing something.
And what's the math that we are talking about here?
Again, this is just multiplying, right?
It's multiplying your time by the dollars per hour.
When you stop and do the math,
you find that some of your decisions don't shake out the balance
the way you thought they were going to.
Now, the reason you have to value your time and look out for yourself,
is because no one else out there is going to do that.
The Martha Stewart Living website has organizing tips
that are going to make your life better.
This one says that you should in your pantry keep a clipboard
for every time you take a scoop of Cheerios
or a teaspoon and a half of salt,
you should write that down, so you know when everything is going to run out.
Because you know, picking up the box and shaking it doesn't work.
I don't know that any responsible person has ever sat with a stopwatch
to see what kind of time that chews up,
if you did that day after day and week after week.
Another tip on there said
you should print out little calendar shaped labels
and put them all on the food in the freezer
so you know what date they went in.
You know, a marker works just fine, and takes like five seconds.
Again, no one is valuing your time, so it's not easy to see what the cost is.
Again, as with jury selection, the DMV,
when you multiply this out over lots of people
you get bigger and bigger effects.
And sometimes with the best of intentions. Look at the volunteering world.
Charities are happy to ask for our time to help them fund raise, right?
To bake for the big sale,
to round up the auction items or sell ruffle tickets.
I've never seen a non-profit after the fact add up everybody's hours
to see how much was put in,
and how does that line up with the money that was raised.
Obviously there's a value to volunteering.
It feels good, people bond, they're working towards a cause.
But if this is a charity that's really depending on that funding,
the top priority really is to raise money.
And if we are not doing the math to value the time,
we might not know whether we're getting the most out of it.
Now, we see a common theme here,
which is that when we don't see the numbers,
it's harder to think about them.
When your chocolate wrapper tells you that calories exist only if you count them
it's not actually true, they are there.
And there are all kinds of numbers that whistle by us all the time,
that we are not thinking about it.
So quick, how many of you know
how much income tax you've paid this year since January?
Kind of have to stop and think about it, right?
Which is scary, because it is one of the biggest chunks of change
we hand over to somebody else every day.
But why don't we think about it? Because we don't see it.
We never possess some of that money to begin with,
so we don't have to hand it back.
And when we do catch of a glimpse of it on a pay stub,
it's usually weekly or biweekly, it's little slices of numbers.
We don't sense how the numbers pile up. We are not doing the street math.
Now, that leads to a third way in which we kind of resist doing the math.
And that is because we don't see
how small numbers pile up into the big ones,
we don't see how small numbers are a piece of the whole,
and which pieces of the pie are the important ones.
So, a few years ago, I couldn't understand
why our electric bill kept going up at my house.
Not just the dollars, but the actual usage.
So I crawled into the bushes and learnt how to read our electric meter,
and then I went and turned off everything in the house,
and I turned on one thing at a time
to see what happened to the electric meter and how much everything was using.
And I was stunned by what I found.
After the air conditioner,
the biggest user of electricity was the clothes drier.
We kept having more kids and more kids is more laundry.
More loads per week, more loads per month.
The kids keep getting bigger and dirtier. We just keep doing more laundry.
And that really started to add up. And that's what was driving it.
And once we zeroed in and realized what fraction of the whole mattered,
we knew the solution.
Stop having children. (Laughter)
Immediately. Because that's where it counts.
So, what's the math we talk about here? Here we are talking about fractions.
Just understanding parts of the whole.
Americans hate fractions.
It is the cliff that every kid,
a lot of kids fall off when they take standardized tests.
This is the reason that restaurants have to calculate the tip for us.
Because taking one fifth makes us nervous. It's not a comfortable topic.
But, if there is one form of street math we need to do,
it's understanding parts of a whole,
and how we can find the highest priority thing to tackle.
So, look at road rage. If you're driving 60 miles an hour,
yes, you can go a little faster by weaving in and out of traffic,
beeping at the idiot in front of you.
You might be able to add on three miles an hour.
As you see, that's really a tiny piece of the total.
You have to drive an hour and 40 minutes just to gain five minutes,
if that's the gain you're getting,
because it is a small fraction of the total.
Or, when you're looking at a budget.
You know, chopping 20 percent out of the yellow wedge fills good.
But chopping 20 percent off that other piece is a lot better.
When we know how the pieces line up, we make better decisions.
We can see many cases in society where we don't find the lever
that's really going to move the needle.
A perfect example is the SAT.
This is the test that high schoolers take that will make a break in many cases,
their choice of college they are going to get into.
And if you line up kid's scores against their family income,
you see that the wealthiest kids score the highest,
the poorest kids score it lowest,
and everybody else falls neatly on a straight line between the two.
And there's a really big gap.
And people argue that test prep is what's making that happen.
It turns out if you look at the mock numbers,
test prep gets you an average about a 30 point gain.
It doesn't explain the 400 point gap over the 3 sections added up
for the wealthiest kids versus the poorest kids.
And that's because 50 hours of test prep is not what we're looking at.
What we're looking at is 16 or 17 years of living a completely different life.
Compared to the kids who are in trouble,
kids who live comfortably eat 6,000 more meals,
because they've got breakfast every morning.
They're going to school well-fed and ready to learn.
They're being read to, sometimes 10,000 more hours,
because their parents know to do that and can afford to take the time.
They live in a house with 50 books per child,
rather than on our poorest neighborhoods,
where it can be one book for every 300 kids.
So, by the time they've gotten here, they've lived a 140,000 hours
of a life that is completely different.
50 hours of test prep is not going to turn it around.
The math here is easy, right?
30 points? Or the remaining 370 that we should be thinking about.
And by the way, schools are only part of the solution.
Before we beat on schools and teachers
for not getting our lowest performing kids to perform,
you have to remember that of the 8,800 hours
that a kid lives in a year, they spend about 1,100 in school.
It's only part of the equation.
For kids who are already in high school,
we can't rewind and redo what has happened.
Test prep is all that's left.
That's why it's so admirable that Sal Khan at Khan Academy,
and David Coleman at the College Board,
are working to have free access for everybody to test prep.
It's a good thing it's free, because these kids need a lot of it.
Not even just to do well on this test, but actually to learn the skills.
To have the reading and the math skills that we are talking about
to be able to live everyday life.
And for the kids who haven't got in high school yet,
it's a time to think about doing a different calculus
on how our communities provide a fabric and a network for these kids.
How we can provide more awareness, and support, and resources for parents,
so that we can nurture the potential on every single kid.
So as we see, numbers shine bright light into dark corners
that we might not want to look into.
But we have to look into them, right? Because this's how we turn around society.
So, how do we turn this around?
I think there are three distinct parts to this.
One is that from the get-go, kids should learn to love math
as something that is not only fun, and cool, and beautiful,
but totally woven into their normal life.
You know, at night we read to kids,
and so they learn to love books, and as adults we read for pleasure.
I never hear people talk about "math for pleasure," right?
And that should change.
Kids should see that it is really part of their playtime and their normal life.
Secondly, in our schools, regardless of what curriculum we are arguing about,
it has to tie-in with real life and decision making.
Kids should taste the excitement of the victory of a good decision.
That's what our math should look like.
Because that's what they're going to do every day as grown-ups.
And, finally, for those of us who already are grown-ups,
we have to retrain our thinking, we have to do the street math.
We have to see how there are numbers behind everything around us,
and in every decision we make,
and that there's a number in every object, and chunk of time, and chunk of money.
If we are aware of that, we can make the better decisions.
And in most cases the numbers are all out there waiting for us.
We just have to do the math.
Thank you.
(Applause)