Somos treinta

This little difference between English and Spanish grammar is easy to overlook: When counting people, English tends to use an existential structure like There are/were ... of us/you/them. However, in Spanish the people to be counted are cast as the grammatical subject — if the speaker or the listener is included in the group. Here are some examples:

• Somos eight. There are eight of us (eight people in my family). The first person plural form is used because the speaker is included in the group.
• Éramos cuatro. There were four of us (living in the house then). Note that the verb is rendered in the imperfect.
• ¿Son seis? There are six (in your dining party)?

When you hear this usage, don't be fooled into thinking that the speaker is discussing age. The English sentence We are thirty means We are thirty years old. However, its word-for-word Spanish counterpart, somos treinta, would mean There are thirty of us.

Haber

When neither the speaker nor the listener is included in the group, use haber: Había tres personas esperando en el andén. There were three people waiting on the platform. Had you been among those waiting, you would have said Erámos tres esperando en el andén.