Adding Using the LCD
Let’s finish adding 
and 
:
The least common denominator, LCD, is 2 . 2 . 3 . 5. To get the LCD in the first denominator, we need a 5. To get the LCD in the second denominator, we need another 2. We get these numbers by multiplying by form of 1:
Multiplying by 1
= 
Each denominator is now the LCD.
= 
Adding the numerators and keeping the LCD
= 
Factoring the numerator and removing a factor of 1: 
= 1
= 
. Simplifying