It's pretty easy to learn and I memorised it in an afternoon with the help of this video so I have shared it here for you to take advantage of too. It's from Mahalo.com and they do lots of Korean Language Videos on You Tube so check them out.
The Korean system uses the same Arabic Numbers that English does but they have their own words for the numbers and so also have the Hangul (Korean Language) written word for each number.
Sino-Korean Numbers 1-10
To make the higher numbers it's pretty easy, 11-19 you just say (10 + number) so for example to say 15 is ship-oh.
When you get to 20-99 you just switch it around (number + ship) so for example 20 is ee-ship and 60 is yuk-ship. The in-between numbers you just add another number on the end for example 23 is ee-ship-sam and 79 is chil-ship-gu and so on.
When you get even higher each place marker has its own new word:
The rules for forming the numbers remain the same so to say 312 you say Three + Hundred + Ten + Two sam-baek-ship-ee and to say 1475 you say cheon-sa-baek-chil-ship-oh.