Half is a weird word because it can be either singular or plural.
Example 1: Half of a pie was left after we each ate a slice.
In this sentence, a singular verb (was) is used since I am referring to half of a singular object (pie).
Example 2: Half of the sodas were left after we each drank one.
In this sentence, a plural verb (were) is used since I am referring to half of multiple objects (sodas).
Fractions can be tricky since sometimes they are plural, even though a fraction is usually less than 1. For example, all of the following are correct:
- Three quarter teaspoons
- Three quarters of a teaspoon
- Three eighths of a truckload
- .375 truckloads (read aloud as “point three seven five truckloads”)
Usually in writing, it’s best to write a fraction as “half” or “three eighths,” etc. Only use decimals when it is important to be accurate and a simple fraction can’t be easily conveyed, as in “that house is worth $3.279 million.” If the house were worth $3.5 million, you could say “that house is worth three and a half million dollars” or “that house is worth $3.5 million.” It all depends on the context.
There really isn’t a rule that applies across the board with fractions, so sometimes it is best to check a dictionary if you are unsure. Or you could always check with your editor!