1. Unlike Denominators: Two or more fractions are said to have unlike denominators when they both contain the different denominators.
Adding or Subtracting Fractions with Unlike Denominators.
1. Find the LCD for each fraction.
2. Write each fraction as an equivalent fraction using the LCD for the denominator.
(Note: Some students prefer to write the fractions vertically.)
3. Add or Subtract the Numerators. Write the result over the original denominator.
4. Reduce if possible.
Step 1. Find the LCD
Solution:
Step 2. Write as equivalent fractions.
Step 3. Add the like fractions and reduce if possible.
Your Turn Problem #1

2. Step 1. Find the LCD
Solution:
Step 2. Write as equivalent fractions.
Step 3. Subtract the like fractions and reduce if possible.
Your Turn Problem #2

3. Step 1. Find the LCD
Solution:
Step 2. Write as equivalent fractions.
Step 3. According to the Order of Operations, left to right with addition and subtraction.
Your Turn Problem #3

4. Solution:
The perimeter of a rectangle is the sum of all the 4 sides.
Option #1: Add the two pairs with like denominators 1st. Then add those two fractions.
Option #2: Find the LCD and add all at once.
Either is fine.
Then reduce and change from an improper fraction to a mixed number (or change to a mixed number, then reduce the fraction.
Your Turn Problem #4
During May, Malibu had 11/14 inches of rain and Fontana had 7/12 inches of rain. How much more rain did Malibu have than did Fontana?
The End.
B.R.