Learn Swedish: De måste samarbeta och hjälpa varandra. - They must cooperate and help each other.

Varandra means 'each other'. It is a reciprocal pronoun, which means it shows that two or more people are doing an action to each other. It is very easy to use because it only has one form, so it never changes based on gender or how many people are involved.

Why are samarbeta and hjälpa in their infinitive forms instead of present tense?

They follow the modal verb måste (must). When you use a modal verb in Swedish, the action verb that comes after it is always in its infinitive (dictionary) form, and you do not use the word att (to). Since both verbs are connected by och (and) after måste, they both stay in the infinitive.

Is samarbeta related to the verb arbeta (to work)?

Yes! Samarbeta is a compound word made of the prefix sam- (together) and arbeta (to work). You will see sam- in many Swedish words that involve doing things together, like sambo (living together) or samtal (conversation).

As a quick reminder, how is De pronounced here?

Even though it is spelled De, it is almost always pronounced as dom in spoken Swedish. It is good to keep this in mind so you are not confused when listening to native speakers.