please tell the difference between a few and few

Dear Student, 

Few means very few ​​​​​​or almost none or a very small number.
Eg: Few people think that smoking is healthy.
It means that a remarkably small number of people think that smoking is healthy.

A few means some or not a large number.
Eg:- A few people think that smoking is healthy. 
It means that some people think that smoking is healthy.

Regards,