| 0–15 | each has its own word | once / quince | eleven / fifteen |
| 16–29 | one word: dieci- or veinti- and the unit | dieciséis / veintidós | sixteen / twenty-two |
| 31–99 | the tens, y, the unit: three words | treinta y uno / cuarenta y cinco | thirty-one / forty-five |
| 100 | cien alone or before a noun, ciento before another number | cien euros / ciento veinte | a hundred euros / a hundred and twenty |
| 1000 | mil takes no un and stays the same after any number | mil / tres mil | a thousand / three thousand |
| A1Hundreds | from 200, they agree with the noun | doscientas personas | two hundred people |
| A1millón | a noun: millones in the plural, de before what it counts | dos millones de personas | two million people |
| A1uno | un before a masculine noun, una before a feminine one | veintiún años / veintiuna casas | twenty-one years / twenty-one houses |
| A1Ordinals | primero to décimo; they agree with the noun and go before it | la segunda calle | the second street |
| A2primer / tercer | primero and tercero drop -o before a masculine singular noun | el primer día / el tercer piso | the first day / the third floor |
| Trap | 500, 700 and 900 change their first part | quinientos / setecientos / novecientos | five hundred / seven hundred / nine hundred |
| Trap | no y after the hundreds | ciento veinte / doscientos cinco | a hundred and twenty / two hundred and five |