Subtracting fractions with unlike denominators

Subtract fractions with unlike denominators

What is the difference?

Finding common denominators

When you multiply the two denominators together, you do get a number they both go into, BUT if you want the SMALLEST COMMON MULTIPLE, think LCM.

Think FACTORS

Just like with adding fractions, you have to have the denominators the same! Each "piece" has to be the "same size."

Common=Same

​How do we get a COMMON DENOMINATOR for this problem?

Open Ended

How do you get a common denominator for this problem?

Open Ended

What other denominator could we have used for that problem?

Multiple Choice

When finding common denominators, you only have to change the denominator. The numerator stays the same.

• True

• False