Another

Typical mistakes: 

We need an other chair. 

I've got other three days holiday. 

1. 'Another' is written as one word. 

We need another chair. 

2. Normally, 'another' is followed by a singular noun: we can say 'another day', but not 'another days'. However, 'another' can be followed by 'few' or a number with a plural noun. 

I've got another three days holiday. 

There's room for another few people in the back of the bus. 

Note that instead of 'another three days, we could say 'three more days', but not (in this sense)'three other days'.