A fraction is comprised of two parts: a numerator (the top number) and a denominator (the bottom number). For example, in the fraction 2/3, the "2" is the numerator and the "3" is the denominator. In order to add fractions, you must have a common denominator. A common denominator is a whole number that is a common multiple of the denominators of two or more fractions. For example, 12 and 24 are both common denominators for 3/4 and 5/6.
The following is a step-by-step example of adding two fractions with
different denominators.
Solve: 1/5 + 4/9 = ?
Step 1: Rewrite horizontal problems vertically.
Step 2: Find a common denominator (a common multiple of the denominators of two
or more fractions). For this problem, the common denominator is 45.
Step 3: Multiply 1/5 by 9/9. Rewrite the first fraction as 9/45. Multiply 4/9 by
5/5. Rewrite the second fraction as 20/45.
Step 4: Add numerators together (9 + 20 = 29). Denominator (45) remains the
same.
The correct answer is 1/5 + 4/9 = 29/45.