Is the word order in this clause correct in exercise 10.2

At first I thought this was an error for a (denn) clause which I thought kicked the verb to the end of the sentence.  But, as I write this question, i'm almost remembering a rule about independent clauses like this one retaining natural word order?  Because denn is not capitalized i presume it is presented as a clause of a preceding sentence.

denn sie kommen mit ihren drei Kindern.

because they will come with their three kids.

Should it instead be:

denn sie mit ihren drei Kindern kommen .

Vielen Dank.