Slide 1

2.7 Adding and Subtracting Mixed Numbers 1 Adding Mixed Numbers Procedure: Adding Mixed Numbers 1. Rewrite the problem vertically aligning the whole numbers and the fractions. 2. Add the fractions. If the result is an improper fraction, convert it to a mixed number. 3. Add all of the whole numbers. Solution: Your Turn Problem #1 Step 2. Find the LCD Step 3. Write as equivalent fractions and add. Step 4. Since the result is improper, change it to a mixed number. Step 1. Rewrite the problem vertically. Step 5. Add all of the whole numbers. 126

Slide 2

2.7 Adding and Subtracting Mixed Numbers 2 Solution: Your Turn Problem #2 Step 2. No LCD necessary. Step 1. Rewrite the problem vertically. Step 3. Bring down the fraction and add the whole numbers. In example #1 and your turn problem #1, the fraction part resulted in a mixed number. We then had to carry over the 1 to the left. When performing subtraction, if the bottom number is larger than the top number, it is necessary to borrow. Example: Since 7 is greater than 3, borrow a 1 from the 5 and write it in front of 3. It then becomes a 13. 4 1 2 6

Slide 3

2.7 Adding and Subtracting Mixed Numbers 3 Subtracting Mixed Numbers Procedure: Subtracting Mixed Numbers 1. Rewrite the problem vertically aligning the whole numbers and the fractions. 2. Subtract the fractions. If the top fraction is smaller than the bottom fraction, borrow a 1 from the top whole number. Write the 1 in front of the fraction and convert it to an improper fraction. 3. Subtract the fractions and the whole numbers. Solution: Your Turn Problem #3 Step 2. Find the LCD Step 3. Write as equivalent fractions and subtract. No need to borrow in this problem. Step 1. Rewrite the problem vertically. Step 4. Subtract the whole numbers.

Slide 4

2.7 Adding and Subtracting Mixed Numbers 4 Solution: Your Turn Problem #4 Step 2. Find the LCD Step 3. Write as equivalent fractions to subtract. Step 1. Rewrite the problem vertically. Step 4. Since the bottom fraction is larger than the top fraction, we need to borrow a 1 from the whole number. Then write it in front of the top fraction and convert it to an improper fraction. (Dont write it in the numerator. That would be wrong!) 96 1 Step 5. Now we can subtract the fractions and whole numbers.

Slide 5

2.7 Adding and Subtracting Mixed Numbers 5 Solution: Your Turn Problem #5 Step 2. No LCD necessary Step 3. Borrowing is only necessary when the bottom fraction is larger than the top fraction. In this case, the bottom fraction = 0. So we then subtract. Step 1. Rewrite the problem vertically.

Slide 6

2.7 Adding and Subtracting Mixed Numbers 6 Solution: Your Turn Problem #6 Step 2. No LCD necessary Step 3. In this problem, the bottom fraction is larger than the top fraction. We then need to borrow a 1. Remember that 1 can be written as any number divided by itself. Since the bottom fraction has a denominator of 16, we will write the 1 as 16/16. Step 1. Rewrite the problem vertically. 24 Step 4. Now we can subtract.

Slide 7

2.7 Adding and Subtracting Mixed Numbers 7 When addition and subtraction are combined, work the first two numbers; then from their answer, add or subtract the third. If only addition is involved, add all numbers at the same time. The same process will apply to mixed numbers. Step 1. Work with the 1 st two mixed #s. Step 2. With that answer, add the 3 rd mixed #. Your Turn Problem #7 The End. B.R. 5-30-08