Lesson 1 Add, Subtract, and Multiply Fractions

- Let’s practice solving problems involving fractions.

Warm-up Number Talk: Fluency and Fractions

Find the value of each expression mentally.

$5 \times \frac{10}{5}$
$9 \times \frac{6}{3}$
$9 \times \frac{6}{3}$
$6 \times \frac{12}{10}$

Activity 1 Let’s Make Head Wraps!

Jada and Lin saw a picture of head wraps made of African wax print fabric and would like to make their own.

Jada stitches together 5 pieces of fabric that each have a length of $\frac{2}{6}$ yard. Write an equation to show the total length of fabric Jada used.
Lin stitches together 3 pieces of fabric that are each $\frac{2}{3}$ yard long. Write an equation to show the total length of fabric Lin used.
Who used more fabric? Explain or show your reasoning.

Activity 2 Make 2 Yards of Fabric

Jada and Lin’s moms taught the fourth-grade class how to combine and use fabric pieces for head wraps. The lengths of each piece of fabric are listed here.

\frac{2}{6}

yard

\frac{2}{6}

yard

\frac{2}{6}

yard

$\frac{11}{10}$ yard

1 \frac{2}{5}

yards

\frac{9}{10}

yard

\frac{2}{6}

yard

$\frac{6}{12}$ yard

\frac{3}{6}

yard

\frac{2}{6}

yard

\frac{2}{6}

yard

$\frac{12}{12}$ yard

\frac{2}{6}

yard

\frac{3}{5}

yard

$\frac{2}{6}$ yard

Find as many different combinations of fabric that would have a length of 2 yards as you can. Each piece of fabric can only be used one time. Write an equation for each combination.

Activity 3 Play by the Rules

Problem 1

Here are four fractions:

$\frac{15}{12}$

$\frac{7}{12}$

$\frac{21}{12}$

$\frac{18}{12}$

What is the sum of all the fractions?
Select two fractions with a difference that is less than $\frac{1}{3}$ . Show or explain your reasoning.
Select two fractions with a sum greater than 3. Show or explain your reasoning.

Problem 2

Here are four new fractions:

$\frac{5}{12}$

$\frac{8}{12}$

$\frac{3}{12}$

$\frac{2}{12}$

Use them to make the value 1, following these rules:

Use addition, subtraction, or both.
Use all four fractions.
Use each fraction only one time.

Problem 3

Try to make the value of 1 again using the following fractions and the same rules.

$\frac{15}{10}$

$\frac{13}{100}$

$\frac{53}{100}$

$\frac{9}{10}$