When you're multiplying fractions by an integer (or a whole number) you multiply the numerator of the fraction by the whole number, whilst the denominator of the fraction stays the same.

A fraction can be a proper fraction or an improper fraction. An improper fraction written as an integer with a fraction is called a mixed number.

it will convert to an improper fraction ("5 1/3") or an integer. To stop this automatic simplification, you need to tell Excel what denominator to use. In other words, to keep "4/6" as is ...