Question

Read the sentence. I spend about half my time, he spends two thirds of his time, and she spends a quarter, or maybe a third, of her time on research. Where in the sentence should the writer add a hyphen? I spend about-half my time, he spends two thirds of his time, and she spends a quarter, or maybe a third, of her time on research. I spend about half my time, he spends two-thirds of his time, and she spends a quarter, or maybe a third, of her time on research. I spend about half my time, he spends two thirds of his time, and she spends a quarter, or maybe a-third, of her time on research. I spend about half my time, he spends two thirds of his time, and she spends a quarter, or maybe-a-third, of her time on research.

Answer 1

I spend about half my time, he spends about two-thirds of his time, and she spends a quarter, or maybe a third, of her time on research. The hyphen is placed between the words that are describing a fractional number, as it is a single idea. 

Answer 2

I spend about half my time, he spends two-thirds of his time, and she spends a quarter, or maybe a third, of her time on research.

The hyphen goes between two and thirds so that it is clear that two and third are connected. Hyphens are used when two words are used together to create one meaning. Two and thirds are used together to show that he only spent a fraction of his time (2/3) researching. In the other options about-half are two separate ideas about and half. The same with a and third; they both are not numbers.