Operations with Fractions

Adding and Subtracting Fractions

When adding and subtracting fractions, the first thing to check is if the denominators are the same.

Adding and Subtracting Fractions with Like Denominators

If the denominators are the same, then it's pretty easy: just add or subtract the numerators, and write the result over the same denominator.

For example,

Adding and Subtracting Fractions with Unlike Denominators

If the denominators are not the same, then you have to use equivalent fractions which do have a common denominator. To do this, you need to find the least common multiple (LCM) of the two denominators.

For example,

Multiplying and Dividing with Fractions

Multiplying a Fraction by a Fraction

To multiply two fractions, just multiply the numerators to get the numerator of the product, and multiply the denominators to get the denominator of the product.

For example,

Multiplying a Fraction by an Integer

To multiply a fraction by a whole number, remember that any integer n can be written as the fraction n/1.

For example,

Dividing by a Fraction

To divide by a fraction, multiply by the reciprocal of the fraction.

For example,

See also: Multiplying a Fraction by a Fraction, Multiplying a Fraction by an Integer and Dividing by a Fraction