Adding & Subtracting Fractions with
Unlike Denominators
Example:
1
2
+
2
5
Step 1: Find a common denominator by finding the Least
Common Multiple (LCM)
Multiples of 2: 2, 4, 6, 8, 10, 12, 14…
Multiples of 5: 5, 10, 15, 20, 25…
*They smallest multiple they have in common is
10 so this will be our common denominator.
Step 2: Make your equivalent fractions.
1
2
=
5
2
10
5
=
4
10
Step 3: Add or Subtract using the equivalent fractions
you found.
5
10
+
4
10
=
9
10
Step 4: Check to see if your answer is in lowest terms or
if you need to reduce it.
©Jen Christensen