Learning English

Inspiring language learning since 1943

English Change language

Session 1

What's the biggest number you know in your language? Do you have a word that isn't an actual number but means a really really big number? In this session we have some fun facts and figures about big numbers and also advice on how to pronounce and write them.

Sessions in this unit

Session 1 score

0 / 10

  • 0 / 0
    Activity 1
  • 0 / 5
    Activity 2
  • 0 / 5
    Activity 3

Activity 3

Billions, trillions and above

A billion

In British English a billion used to mean a million million, that's 1,000,000,000,000. These days however, the American English version meaning a thousand million (1,000,000,000) is universal.

In 2013 the population of the planet was estimated at 7.13 billion.

This would be said as seven point one three billion.

The universe is believed to be about 13.8 billion years old.

This would be said as thirteen point eight billion.

If you remember from the previous activity a million seconds is over 11 days. How long is a billion seconds? Any idea. Are we talking days? weeks? months? Find out in the quiz below!

A trillion

This is a really big number! 


If you were a dollar trillionaire and spent a million dollars a day, every day, for your whole life and if you lived to be a hundred you would still have more than $600 billion left at the time of your death.

Numbers in the trillions are perhaps the biggest numbers that we are familiar with hearing. They often feature in news reports about various governments' debts.

A zillion / a gazillion

Okay, these aren't real numbers, but they are real words. We use them to emphasise a very large number of things.

  • It was disgusting. I lifted up the carpet and there were a gazillion ants underneath.
  • Don't advertise your party on social media - you don't want a zillion people turning up. 

Read the text and complete the activity

The biggest numbers of all 

Numbers above the trillions are pretty meaningless for most of us. They are outside our experience and understanding - but they do exist.

The largest number in the dictionary that has an -illion ending is a centillion. That's the number 1 followed by 303 zeros.

Perhaps the largest number that has a name is a googleplex. That's 1 followed by a googol of zeros. What's a googol? It's the number 1 plus a hundred zeros.

What about infinity?

Infinity means 'never ending', so is infinity the biggest number? If so, what is infinity +1?


To do

Just for fun, try our numbers quiz.

Numbers quiz

5 Questions

Can you get the right answers to these questions about big numbers?

Congratulations you completed the Quiz
Excellent! Great job! Bad luck! You scored:
x / y

End of Session 1

That's all for this session. In the next one you can 'count on us' to teach you all about linking devices of contrast. See you there!

Session Vocabulary

  • Really big numbers

    a billion (1,000,000,000)

    a trillion (1,000,000,000,000)

    a zillion / gazillion (used for emphasis, not real numbers)