Adding Fractions

To add fractions, they must describe pieces of the same size, so you first rewrite both fractions with a shared denominator. Multiplying each fraction by a form of 1, such as d/d or b/b, changes the appearance without changing the value, and the numerators combine into ad + bc while the common denominator becomes bd. This gives an equivalent fraction that represents the total amount.

Use this when adding any two fractions, whether in arithmetic problems, measurements, recipes, or probability questions. It is especially useful when the fractions have different denominators and cannot be combined directly.

• Adding the denominators as well as the numerators
• Forgetting to use a common denominator before adding
• Not simplifying the final fraction or mixed number