I need help with counting

Question

so, I know I write 16 as dieziseis but when do I start to seperate the numbers? example: treinta y uno

Answer 1

After 29.

16=dieciséis
17=diecisiete
18=dieciocho
19=diecinueve
21=ventiuno
22=veintidós
23=veintitrés
24=veinticuatro
25=veinticinco
26=veintiséis
27=veintisiete
28=veintiocho
29=veintinueve

Answer 2

Please have a look [url=http://my.spanishdict.com/vocabulary/vocabulary/show'id=1710195%3ATermList%3A1006213]at this list[/url] for practising numbers.

On the vocabulary lists you will find easier lists too. Make a search for "numbers".

Answer 3

From 16 to 29, you have two choices to write the numbers.
16 = dieciséis = diez y seis
21 = veintiuno = veinte y uno

However, starting from thirty, you only have one choice.
31 = treinta y uno