To make up numbers higher than 100 you simply add -hundert in front of the smaller numbers:

 

 

hundert + eins = hunderteins 101
hundert + zweiunddreißig = hundertzweiunddreißig 132

You can link words with und, but it's completely optional.

 

hundert + und + eins = hundertundeins 101
hundert + und + zweiunddreißig = hundertundzweiunddreißig 132

For 200 to 900, you add the number of hundreds in front of -hundert.

 

(ein)hundert 100
zweihundert 200
dreihundert 300
vierhundert 400
fünfhundert 500
sechshundert 600
siebenhundert 700
achthundert 800
neunhundert 900

As you can see, because the numbers are written as one word they can be quite long!

 

vierhundertfünfundzwanzig 425