Wednesday October 20 Blue Thursday October 21 Gold

Wednesday, October 20 (Blue) Thursday, October 21 (Gold) Objective Students add and subtract fractions and mixed numbers • • Fill in planner • Today’s Assignment (Practice 5 -3) Bell Work • Compare the fractions using <, >, or =

Adding Fractions with common denominators Just add the numerators!

Adding Fractions with different denominators Problem: You can’t add fractions with different denominators. Solution: Turn fractions into equivalent fractions with a common denominator, preferably the LCD!

Finding the Lowest Common Denominator • The lowest common multiple of two numbers is the lowest number in BOTH lists of multiples Example 1 Multiples of 2 are 2, 4, 6, 8, 10…… Multiples of 3 are 3, 6, 9, 12, ……… What is the lowest common multiple?

Finding the Lowest Common Denominator • The lowest common multiple of two numbers is the lowest number they will BOTH divide into 2 divides into 2, 4, 6, 8…. . 3 divides into 3, 6, 9…. What is the lowest number 2 and 3 both divide into?

You can’t add fractions with different denominators + The Lowest Common Multiple of 2 and 3 is 6 so turn all fractions into sixths Special form of 1

Example 2 Lowest common denominator is 10 so make all fractions tenths

Example 3: Turn both fractions into twelfths

Variable Expressions Example 4

Variable Expressions Example 5

Variable Expressions Example 6

Adding Mixed Numbers Find the sum. 1 + 3 4 4 9 1 9 5 9 1. Rewrite the fraction using LCD if denominators are different. 2. Add or subtract the fractions, then the whole numbers. 3. Simplify if possible. In this problem, the denominators are the same, so begin with step 2.

Let’s Do More Examples! Example 8 1 + 3 4 Example 9 4 4 9 1 3 7 9 X 3 = X 3 3 9 + 5 7 8 X 2 1 4 = X 2 8 9 9 10 2 8 1 8 = 1 1 8 Add the whole numbers.