Lowest Common Denominator
Definition

The lowest common denominator is another name for the least common multiple of the denominators.


Fractions are usually expressed with the lowest common denominator when they are compared, added or subtracted.

Example One

PROBLEM


Which of the following fractions is larger?

Example one fractions

SOLUTION


Re-write the fractions wich a lowest common denominator of 60.

Calculate the multipliers
Example one: fractions with the lowest common denominator
Example one conclusion
Example Two

PROBLEM


What is the sum of the following?

Example two fractions

SOLUTION


Re-write the fractions wich a lowest common denominator of 36.

Calculate the multipliers
Use the lowest common denominator to add the fractions