One of the first things you learn in a new language is how to count, and this course is no exception. However, in Lojban, numbers include much more than just counting; for example, in Lojban, some, most and too many are numbers.
The numbers from one to nine are as follows:
pa
re
ci
vo
mu
xa
ze
bi
so
Numbers from 10 onwards are made by putting the digits together, just like you'd say a telephone number. For example:
pano  10  
zebi  78  
xanoci  603  
vomusore  4,592 
Just as we have a word for a comma, we also have one for a decimal point: pi. So 5.3 is mupici. In fact, pi is not always decimal; it's the point for whatever number base you're using. But that's a more advanced topic.
Tip: Don't get this mixed up with the number pi (π): 3.14159..., which has its own word in Lojban: pai — oddly enough.
When you want to talk about numbers as sumti — that is to say, as things in and of themselves — you need to put an article in front of them. But that article cannot be la, and for reasons which hopefully will become clear soon, it cannot be le either. In front of numbers, Lojban uses the article li. So li pareci means 'the number one hundred and twenty three'. 'One, two, three', on the other hand, would be li pa li re li ci: each li introduces a brand new number.
Exercise 1 
What are the following numbers in Lojban? (don't forget li!)
