Usually, double negatives are absolute No-No anywhere. But, I bring this up for discussion because I see some of us use them—in workplaces and outside. Now, why would we use them? Because we hear people around us using them. Simple logic: if everyone is using it, it must be right. Oh, you can blame it on Hollywood’s portrayal of the good Ol’ Texas ranches and Cowboys, too.
A double negative is when you use two negatives together. For example, “I don’t know nothing.” The trouble is that there are exactly two interpretations of it. First, the obvious deduction “I know, at least, something.” And, second, its distant cousin, “I, literally, don’t know anything.” It is quite possible that while you wished to say (and mean) the latter one, you end up being understood as meaning the first one. It is confusing.
So, AVOID using it. How do you avoid using it? Simple. Use one negative expression. Just say (and, hopefully, mean) “I don’t know anything”.
But, not always will you or can you avoid. For example, “She didn’t go unnoticed in the party”. In this case, we wish to say that there, indeed, was someone who took a notice of her. You should dare to use a double negative only in situations like these. I say dare for a reason: look at the title of this post. Did you see how in some cases two negatives make a positive?
Let us say, the English and math do have something in common. The exception is, two “minuses” don’t always make a “plus” in the English language.