There are patterns that will help you memorize numbers.
11 to 15 all end in -ce:
11 once 12 doce 13 trece 14 catorce 15 quince
16 to 19 start with diez, ten
16 dieciséis - literally diez y seis, ten and six 17 diecisiete 18 dieciocho 19 diecinueve
20 to 30: the final -e of veinte, twenty, changes to -i
30 to 90: they all end in -nta.
30 treinta 40 cuarenta 50 cincuenta 60 sesenta 70 setenta 80 ochenta 90 noventa
31, 42, 53...etc. For the intervening numbers, you need y, and:
31 treinta y uno 42 cuarenta y dos 53 cincuenta y tres
...and so on.
100 - this is cien
