"A is x Times Less Than B"

Nonsense.

Or x times fewer than something, or x times smaller than something, x times shorter / slower / cheaper / thinner / weaker – All nonsense!

• "times" is a multiplier, as in:   3 times 2 is 6.
• "smaller than", "less than" etc. indicate subtraction, as in:   2 less than 10 is 8.

With that in mind, let's look at a few examples:

John worked 200 hours last month. Bill was on vacation most of that time, so he worked 10 times less than John.

If Bill worked 1 hour less than John, he would have worked 200 - 1 = 199 hours.

But Bill worked "10 times" less than John. What is "10 times" in hours? Ten times the amount of John's work is 10 x 200 = 2,000 hours.

Great! Now let's use that:
Bill worked 2,000 hours less than John. In other words Bill worked 200 - 2,000 = -1,800 hours.

Huh ???

Bill worked a negative 1,800 hours last month? I think not. See now how this is nonsense?

This special paper is 5 times thinner than a human hair.

How thick would it be if it was one time thinner?
Zero?
But presumably the paper does exist, so it must have SOME thickness. Strangely, as you make it even more times smaller, it starts getting thicker again, coming back up from zero?

To contrast, consider this one:

I complain: "I have \$20,000 debt."
You brag: "Ha, I have \$10,000 savings in the bank."
I'm crushed : "Dude, I have 3 times less money than you."

You have \$10,000. Three times your money is \$30,000. Three times less your money is \$-20,000, exactly the amount of my debt.

This is a rare example where it makes sense. It works only because a bank account can go into the negative. Most other things in life, such as the weight, thickness, length, age, etc. cannot. And it's not what people usually mean anyway.

How to do it right? In the first example, Bill probably worked 20 hours that month. So you can say:

• "John worked 10 times more than Bill."
• "Bill worked a 10th of John's hours."
• "Bill worked 10% of John's hours."
• "Bill worked 90% less than John." by Paul Brians 