Adding and Subtracting Fractions With different denominators

Different Denominators                                                                                 Different Denominators It's easy to add and subtract like fractions, or fractions with the same denominator. You just add or subtract the numerators and keep the same denominator. For example,                                                the answer is

Least Common Denominator The least common denominator (LCD) of two or more fractions is the smallest number that can be divided evenly by each of the fractions’ For example if you have 1 and 1 what is 3 4 the least common denominator?

Adding Fractions You just add the numerators and keep the same denominator.

Subtracting Fractions You just subtract the numerators and keep the same denominator.

Least Common Denominator We need some way to determine which fraction is larger. Suppose Marcia and Melissa have some left over pizza.

Least Common Denominator We can compare using slices of pizza. If each person had 12 slices we can see Marcia had 1/12 more slices than Melissa.

Steps in finding the LCD Convert unlike fractions to equivalent like fractions. Find the smallest number that can be divided by both denominators. This will be the least common denominator.

Finding the LCD To find the smallest number each denominator can be divided into start by doing the following: 4 4, 8, 12, 16 6 6, 12, 18, 24 The of 4 and 6 is 12. can be divided into can be divided into LCD

Create New Fractions Next divide the original denominator into the new denominator (12 divided by 4 = 3). Next, multiply the product by the original numerator (3 x 3 = 9). This results in your new fraction. 3 9 12 Multiply by original numerator new fraction Divide original denominator

Add the new fractions 9 + 2 = 11 12 12 your answer is

Turn in your answers within 10 minutes. Practice Find the LCD for each pair of fractions. Remember the steps!!! Turn in your answers within 10 minutes.

Practice Answers Here are the answers to your problems.

Online Extra Practice Try out these examples on the following online resources: Least common multiplier Least common denominator Interactive Tutorial

Games are Cool Practice! Check out this website to try you chance at some least common denominator games. Race against the clock to test your skills. Visit the following site to play the game! Least common denominator game

You Did It!!! Give yourself a pat on the back. Keep up the good work. Here’s a reward especially for you! APPLAUSE!!!