5 Minute Math 3. Place the following fractions in increasing order: 3/4 2/5 6/10 17/20 1/2 4. Match each colored shape with one of the following fractions: 1/3 1/5 1/10 11/30

Adding & Subtracting Fractions When the Denominator of One Fraction is the Multiple of the Other Fraction(s)

Learning Goal We will be using our prior knowledge of equivalent fractions so that we can add and subtract fractions. We’ll know we’ve got it when we can add and subtract fractions using equivalent fractions.

Adding & Subtracting Fractions with Common Denominators When you need to add or subtract fractions and they have a common denominator, just add or subtract your numerators! 1/6 + 4/6 = Because… 1 + 4 = 5 11/12 - 4/12 = Because… 11 - 4 = 7

Fractions with Different Denominators If you have to add or subtract fractions with different denominators, put them over a common denominator. To do this, find the greatest denominator. 1/3 + 2/9 1/3 – 2/9 Check whether the greatest denominator (9) is a multiple of the other denominator. If it isn’t, find the lowest common multiple. Convert the fraction (1/3) into an equivalent fraction with 9 as the denominator. 9 becomes the common denominator.

Fractions with Different Denominators Add or subtract the fractions, which now have the same denominator. 1/3 + 2/9 = 3/9 + 2/9 = 1/3 – 2/9 = 3/9 – 2/9 =

You Can Also Use a Grid 1/3 = 3/9 + 2/9 = 5/9 1/3 = 3/9 - 2/9 = 1/9

But, What If I Have MORE Than 2 Fractions?!? Follow the same process – find the greatest denominator and make all your fractions equivalent 3/8 + 1/4 + 3/16 Since 16 is the greatest denominator, convert 3/8 and 1/4 to equivalent fractions: 3/8 = 6/16 and 1/4 = 4/16 Then, add them up: 6/16 + 4/16 + 3/16 = 13/16