Look at how we say large numbers.

 

800 eight hundred         80 000 eighty thousand          50 000 000 fifty million

 

When we use an approximate number, we add - s and of.

 

There are hundreds of currencies / thousands of banks / millions of people in the world.

 

Look at how we say these numbers

 

157                     a / one hundred and fifty-seven

579                    five hundred and seventy-nine

5 790                 five thousand seven hundred and ninety

57 901                fifty-seven thousand nine hundred and one

5 790 000          five million seven hundred and ninety thousand

 

When we talk about exchange rates, we can say the decimal point (.).

 

$1.34                  There are one point three four US dollars to the euro.

 $239.34              There are two hundred and thirty-nine point three four dollars.