This does NOT mean that you should be counting words in the exam. If you have time to count words in the exam then you have not done enough. You should go into the exam with a good idea of how many lines/ pages 150 and 250 words is in your writing.
This also does NOT mean that you can simply repeat words or copy the title. If you do then this might be taken out of the word count. You must rephrase the title and try to use synonyms throughout your writing.
Small words like 'a' and 'an' DO count as single words but contractions such as 'don't' and 'won't' would only count as one word.
The important thing to note here is that word count counts. Do NOT ignore it.
Vocabulary:
at least = the minimum
state (v) = say, write
rephrase (v) = rewrite, write in a different way
synonym (n) = a word with a similar meaning
note (v) = notice