One (1) can take the form of a fraction. This property will be important when you add or subtract fractions with unlike denominators  Any whole number can be converted to a fraction by simply placing it over ONE. 
A whole number combined with a fraction creates a mixed number. 

To convert an improper fraction into a mixed number, divide the numerator by the denominator and use the remainder as the new numerator. 
To convert a mixed number to a fraction, multiply the whole number by the denominator and add the answer to the numerator. This new number becomes the new numerator. Keep the original denominator. 