You might write that you want fewer mistakes and less inefficiency in your business writing or office. But, it would be incorrect to write that you want less mistakes and fewer inefficiency. Why is that?
The answer lies in the type of noun each word modifies. Mistakes and inefficiency are different types of nouns. Mistakes is a countable noun and the inefficiency is uncountable.
Countable nouns are things like reports, products, ideas, employees, and managers. They are countable because you can have 1 employee or 1,000 employees. The word employee can be made plural, and therefore, you can count the word employee.
Uncountable nouns are things like efficiency, money, and electricity. You might be able to count these things (we all count money every day) but you cannot count the word money. You simply cannot have 1 money or 1,000 monies.
It is correct to use fewer with countable nouns, and less with uncountable nouns. After taking a vacation, you have less time off remaining, but you could also say that you have fewer days off remaining. Time is uncountable so it is used with less, while day is countable so it is used with fewer.
Similarly, items are countable, so the common sign "10 Items or Less" seen so often in markets is grammatically incorrect. It should state "10 Items or Fewer."
Fewer and less are not the only words that are unique to one type of noun. Here are other examples:
|A few/Few||A little/Little|
There are some words that can be used with both countable and uncountable nouns. These are: some, plenty of, a lot of, and any. You can have some employees and plenty of electricity, as well as plenty of employees and some electricity.
Note: When using any of these modifiers with countable nouns, the noun must be plural. For example, fewer hours, many reports, a few days, several ideas, and a couple of managers. It would be awkward (and grammatically incorrect!) to say fewer hour or several idea.
Be careful! There are quite a few words that used as countable nouns even though they are technically uncountable. A good example of this would be coffee. We all say, “I'll have two coffees, please.” But, this is technically incorrect (it should be two cups of coffee). It is worth remembering that certain nouns (coffee, water, beer, etc.) are uncountable even when used as countable nouns. If you remember that, you will be more likely to choose the correct quantifier. This is important because even though it's not a problem to say, “I drink two coffees per day,” it is a problem to say, “I need to drink fewer coffees.”
If you are ever in doubt, consult a good dictionary, which will differentiate between countable and uncountable nouns. The nuances of countable and uncountable noun usage may seem small, but they are invaluable to the clarity and ease of your business writing.
Remember, business grammar errors are always very individual. To correct your errors, it isn't helpful to review all business grammar rules. Instead, choose an overall business writing course or business grammar course that provides individual review and feedback on your writing so you can focus on your specific errors.