Which of the following best describes a fraction?

A fraction is best described as a part of a whole, represented with a numerator and a denominator. This definition highlights the essential components of a fraction: the numerator indicates how many parts are being considered, while the denominator signifies the total number of equal parts into which the whole is divided. This concept is fundamental to understanding fractions, as they are used to represent portions of a whole entity, be it in mathematics or in various applications such as cooking, finance, and measurement.

The other options do not accurately capture the definition of a fraction. For instance, describing a fraction as only a whole number with no decimal does not encompass its true nature, since fractions can represent non-whole quantities. Additionally, referring to a fraction solely as a measurement of angles misrepresents it, since while angles can be expressed as fractions, that is not their only application, nor does it define what a fraction is. Lastly, limiting the application of fractions only to addition and subtraction overlooks their use in multiplication and division, which are also critical operations involving fractions.