Hi everyone! Did you enjoy finding out a bit more about Georgina? She’s told me that she’s had a lot of very positive feedback about her TEDx presentation, so thanks to those of you who contacted her. Those of you who have not yet checked out her video, why not and get on it!

This week we’re going to concentrate on **numbers**. Reading numbers, and particularly saying them out loud, can be one of the most confusing things for language learners. This is partly because as soon as you see numbers or try to do a calculation, your brain immediately switches to your first language. **Don’t worry! This is perfectly normal!**

One way to study numbers both large and small in context is to look at a topic that is at the centre of almost every economic and environmental debate imaginable: **population**. I have written out every number that I’ve used in words so that you can** say them out loud** as you read the blog. **Go on – make your colleagues think that you’re mentally ill!**

Let’s begin with a few questions:

**How long have we been here?**

** How many people are there in the world today?**

**What is going to happen to world population in the future?**

Let’s start with the first question: **How long have we been here?** The Natural History Museum website estimates that our earliest ancestors, *hominins*, lived in Africa between 6 (six) and 7 (seven) million years ago. They probably lived in forests and spent some of their time walking on two feet. They would have looked like a cross between a monkey and a human, or more or less like I look in the morning. People as we know them now have been around for about 200,000 (two hundred thousand) years, and now there are lots and lots of us. But would you believe that we nearly didn’t survive?

Several theories suggest that at different times in the past 2 (two) million years **humans have experienced ‘population bottlenecks‘**, where the total number of humans on earth has fallen to near-extinction levels. One of these, the Toba catastrophe theory, posits that** about 70,000 (seventy thousand) years ago a quite frankly enormous volcano erupted on the present day site of Lake Toba**, in Indonesia.

It is estimated that this eruption was more than 100 (one hundred) times more powerful than any in recent history, and that it caused a global volcanic winter that lasted between 6 (six) and 10 (ten) years.The cooling period after the eruption would have gone on for 1,000 (one thousand) years!

So what did that mean for the people of planet earth? **Well, death, mostly**. Genetic evidence indicates that between 50,000 (fifty thousand) and 100,000 (one hundred thousand) years ago the total number of people on the planet dropped to between 3,000 (three thousand) and 10,000 (ten thousand) individuals, from whom we are all now descended. Those people got busy, to say the least.

Can you imagine living in a world with only a few thousand other people in it? Just imagine how easy it would be to park your car! Queuing would be a thing of the past! Want to go to the beach? No problem! You can have the entire coast all to yourself! Of course, there would be corpses everywhere, but you’d soon get used to that.

How many corpses, I hear you ask? Well, the answer to that is the answer to our second question: **How many people are there in the world today?**

Below is the World Clock by Poodwaddle.com, which shows the current world population according to various estimates.

**At the time of writing that would be 7,226,946,319 corpses.** That number is written: seven billion, two hundred and twenty-six million, nine hundred and forty-six thousand, three hundred and nineteen. That is a reasonably large number of corpses.

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**SOME CRAZY MATHS**

A student of mine and I did a calculation the other day work out the volume of all the people on the planet. I know, it seems like a strange thing to do; in fact it’s a great way to practise speaking English because you often argue over the result!

**Do you think that all the people in the world could fit into a cube measuring 1km x 1km x 1km?**

Have a guess.

My student and I decided to simplify the calculation. We decided to:

– make the total world population a round number; in this case, 7 (seven) billion.

– assume that each person is the same average size, taking into account that about 26% (twenty-six percent) of the people in the world are under 15 (fifteen) years old, and that about 8% (eight percent) are over the age of 65 (sixty-five). We decided that **an average person would be 1.5m tall, 0.3m wide and 0.2m deep** (one point 5, nought point three, nought point two).

The calculation to work out the volume of a single person was simple:

**1.5 x 0.3 x 0.2 = 0.09m³ (nought point oh nine cubic metres)**

Then we just had to multiply the volume of the average person by the total number of people:

**0.09 x 7,000,000,000 = 630,000,000m³ (six hundred and thirty million cubic metres)**

Given that **a cubic kilometre is 1000m x 1000m x 1000m**, which is **1,000,000,000m³ (one billion cubic metres)**

then the answer is

**YES!**

**In fact all the people in the world would only fill about 2/3 (two thirds) of the cube!**

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So that only leaves the third and final question: **What is going to happen to the world population in the future?**

I recently watched a great TED Talk by Hans Rosling, a Swedish medical doctor, academic and statistician, in which he made some predictions about what will happen to world population by 2050 (twenty fifty/two thousand and fifty). You can watch the TED Talk below. **Don’t forget that you can watch the video with English subtitles if you click on the ‘captions’ button underneath the video.**

Did you understand what Mr Rosling meant when he said that he was a “very serious possibilist?” I think that he means that we have a chance to deal with our problems, but that we probably won’t!

**Let me know what you think in the comments box at the end of the blog, or on our Facebook page.**

I’m already looking forward to next time!

Al

**GLOSSARY**

to get on it = to do something immediately

out loud = audibly, so others can hear you

to switch to = to change from one thing to another

ancestors = people who existed before you

bottleneck = a narrow opening that something can pass through (typically wine or beer!)

quite frankly = honestly

cooling = a reduction in temperature

queuing = waiting in a line of people

corpses = dead bodies

to work out = to calculate

a round number = a whole number without decimals

**STOP! SPECIAL GRAMMAR TIME!**

**Some great facts about numbers in English:**

1) We use a point (.) and not a comma (,) for decimals. In fact, we only use commas when we write thousands.

10,001 = ten thousand and one

10.001 = ten point oh oh 1

2) After a decimal point all the numbers are read seperately.

0.174 = nought point one seven four

3) The stress in on the ‘cent’ of ‘percent’.

10.21% = ten point two one perCENT

4) A billion in English is 1,000,000,000 **NOT** 1,000,000,000,000!

5) Alberto Coto from Langreo in northern Spain was world champion in mental claculation between 2008 and 2010. He currently has the world record for adding one hundred single digit numbers in his head, which he did in 19.23 seconds. That’s five calculations per second!

**ALL THE NUMBERS IN THE BLOG IN SIZE ORDER (see how quickly you can say them out loud):**

nought point two

nought point three

two thirds

one point five

two

six

seven

ten

fifteen

twenty-six

sixty-five

one hundred

one thousand

three thousand

ten thousand

fifty thousand

seventy thousand

one hundred thousand

two hundred thousand

six hundred and thirty million

one billion

seven billion

seven billion, two hundred and twenty-six million, nine hundred and forty-six thousand, three hundred and nineteen

**My colleague David and I both tried to say the numbers as fast as we could – I think it’s obvious who won the competition! Can you beat the both of us?
**

## Un Comentario

Interesting post, Al! You won but… only for 1 second!! 😉

Just a question, in what situations ZERO is used? Only with the 0 number, I imagine, is it right?

Thanks!

Carol