Learn Spanish (Spain): Tengo doscientos euros.

In Spanish, the ending of the verb usually tells you who is doing the action. Because tengo only ever means "I have", the word yo (I) is optional. Native speakers usually leave it out unless they want to add special emphasis.

How do you build hundreds in Spanish? Why isn't it just dos cien?

To make the hundreds from 200 upwards, you combine the number with cientos (hundreds) into a single word. So, "two hundred" becomes doscientos (dos + cientos). You only use the word cien by itself when you mean exactly one hundred.

Does the word doscientos ever change its ending?

Yes! The numbers 200 through 999 must match the gender of the noun they are counting. Because euros is a masculine word, we use the masculine form doscientos. If you were counting something feminine, like tables (mesas), you would say doscientas mesas.