A girl and her grandfather baking bread in a sunny kitchen

The Bread Bakers

Maya and Grandpa are baking bread. The recipe needs 2 1/4 cups of wheat flour and 1 2/4 cups of white flour. How much flour is that in all?

4th Grade Math

Step 1: Add the Fractions

1/4

+

2/4

A mixed number has a whole number and a fraction. Start with just the fractions. Add the numerators. What is 1/4 + 2/4?

Add the numerators: 1 + 2 = 3. The denominator stays 4. So 1/4 + 2/4 = 3/4.

Step 2: Add the Whole Numbers

2 1/4 + 1 2/4 = ?

The fractions made 3/4. Now add the whole numbers: 2 + 1. How much flour does Maya need in all?

Wholes: 2 + 1 = 3. Fractions: 1/4 + 2/4 = 3/4. Put them together: 2 1/4 + 1 2/4 = 3 3/4 cups.

What If the Fraction Gets Too Big?

3/4

+

3/4

Grandpa's roll recipe needs 1 3/4 cups and 2 3/4 cups. The fractions add up: 3/4 + 3/4 = 6/4. That is more than one whole! 6/4 is an equivalent fraction for which mixed number?

6/4 = 4/4 + 2/4 = 1 2/4. Now finish the problem: wholes are 1 + 2 + 1 = 4. So 1 3/4 + 2 3/4 = 4 2/4 cups.

Let's Remember

          Adding Mixed Numbers
        
          Step 1: Add the fractions. The denominator stays the same.

          Step 2: If the fraction is one whole or more, regroup it.

          Step 3: Add the whole numbers.

Subtraction follows the same three steps. You will try it soon!

Watch Out!

          A Common Mistake
        
          1 1/4 + 2 2/4 is NOT 3 3/8.

          Never add the denominators!

The denominator tells the size of the parts. Fourths stay fourths when you add them. The correct answer is 1 1/4 + 2 2/4 = 3 3/4.

Now Try Subtraction

0

1/6

2/6

3/6

4/6

5/6

1

Maya's pitcher holds 4 5/6 cups of water. She pours out 2 1/6 cups for the dough. Subtract the fractions, then the wholes. What is 4 5/6 - 2 1/6?

Fractions: 5/6 - 1/6 = 4/6. Wholes: 4 - 2 = 2. So 4 5/6 - 2 1/6 = 2 4/6 cups.

Solve It!

3 2/5 + 4 1/5 = ?

Fractions: 2/5 + 1/5 = 3/5. Wholes: 3 + 4 = 7. So 3 2/5 + 4 1/5 = 7 3/5.

Word Problem

Jade hiked 2 3/8 miles before lunch. She hiked 3 7/8 miles after lunch. How many miles did Jade hike in all?

Fractions: 3/8 + 7/8 = 10/8. Regroup: 10/8 = 1 2/8. Wholes: 2 + 3 + 1 = 6. Jade hiked 6 2/8 miles.

What Goes in the Blank?

2 3/8 + ? = 5 7/8

Hint: addition and subtraction are related. Work backward!

Subtract to find the missing part: 5 7/8 - 2 3/8. Fractions: 7/8 - 3/8 = 4/8. Wholes: 5 - 2 = 3. The missing number is 3 4/8.

Regroup to Subtract

Grandpa says: You cannot take 2/3 away from 1/3! Regroup one whole: 5 1/3 = 4 + 3/3 + 1/3 = 4 4/3. Now you can subtract.

5 1/3 - 2 2/3 = ?

Rewrite 5 1/3 as 4 4/3. Fractions: 4/3 - 2/3 = 2/3. Wholes: 4 - 2 = 2. So 5 1/3 - 2 2/3 = 2 2/3.

Challenge!

A rope is 7 2/8 yards long. Leo cuts off 2 5/8 yards for a swing. Then he cuts off 1 3/8 yards more for a tire. How much rope is left?

First cut: regroup 7 2/8 = 6 10/8. Then 6 10/8 - 2 5/8 = 4 5/8. Second cut: 4 5/8 - 1 3/8 = 3 2/8 yards left.

Think About It

When might you add or subtract mixed numbers at home? Think about cooking, building, or measuring how far you walk.

Great Work!

0/9

correct

mixed number fraction numerator denominator equivalent fraction