Learn Spanish (Spain): Hemos quedado en resumir el primer apartado por la tarde. - We have agreed to summarize the first section in the afternoon.

While quedar often means to meet up or to be left over, adding the preposition en changes the meaning to mutual agreement. The structure quedar en plus an infinitive is the most natural, everyday way in Spain to say you have agreed or decided to do something together.

Is it possible to use acordar instead of quedar en here?

Yes, hemos acordado resumir is perfectly correct. However, acordar feels slightly more formal or professional. For casual plans among classmates or coworkers, quedar en is the go-to phrase.

Why is the word primero shortened to primer here?

The ordinal number primero drops its final -o whenever it comes immediately before a masculine singular noun. Since apartado (section) is a masculine singular noun, you must use primer.

Why do we use por in por la tarde instead of en?

In Spain, por is the standard preposition used for general times of day, so you will always hear por la mañana, por la tarde, and por la noche. You only switch to de when specifying an exact hour, such as a las cinco de la tarde.