[header] How to add mixed numbers [title] Add the whole numbers together. [step] The whole numbers are 1 and 2, so 1 + 2 =3. [title] Find the lowest common denominator (lcd) of both fractions. 
The lcd is the lowest number that is evenly divisible by both numbers. [step] Since the denominators of the fractions are 2 and 4, the lcd is 4, because 4 is the smallest number that is divisible by both 2 and 4.