Now, from 10 to 19 , things are irregular, like in English and in German.

Note: 17 to 19 - you can remember easily those 3 cases:

• 17 = 10+7: dix+sept = dix-sept
• 18 = 10+8: dix+huit = dix-huit
• 19 = 10+9: dix+neuf = dix-neuf