### Let’s Think About It

Josh is at the yarn store for their annual sale. Each bundle of yarn is on sale for $3.49. He buys 10 bundles of red yarn, 8 bundles of green, 6 bundles of blue, and another 6 bundles of yellow. How much did Josh spend on yarn?

In this concept, you will learn to use the distributive property to evaluate numerical expressions.

### Guidance

To **evaluate** an expression means to simplify an expression to find the value or quantity. Expressions of the product of a number and a sum can be evaluated using the distributive property.

Distributive Property

The **distributive property** is a property that allows you to multiply a number and a sum by *distributing* the multiplier outside the parentheses with each addend inside the parentheses.

Then you can evaluate the expression by finding the sum of the products.

Here an expression of the product of a number and a sum.

To use the distributive property, take the 4 and distribute the multiplier to the addends inside the parentheses.

Then, find the sum of the products.

Therefore, the value of the product of 4 times the sum of 3 plus 2 is 20.

Here is another example, this time with a variable.

\begin{align*}8(9+a)\end{align*}

Evaluate the expression using the distributive property. First, distribute the 8 to each addend inside the parentheses.

\begin{align*}8(9+a)=8(9) + 8(a)\end{align*}

Then, find the sum of the products.

This is as far as this expression can be evaluated. If there is a known value for

, you can substitute with the value to continue evaluating the expression.Evaluate the expression if \begin{align*}a = 4\end{align*}.

The value of the product of 8 times the sum of 9 plus \begin{align*}a\end{align*}, when equals 4, is 104.

### Guided Practice

Use the distributive property to evaluate the expression.

First, distribute the 4 and multiply it by each value in the parentheses.

Then, find the sum of the products.

The value of the product of 4 times the sum of 9 plus 2 is 44.

### Examples

Use the distributive property to evaluate the following expressions.

#### Example 1

First, distribute the multiplier to each value in the parentheses.

Then, find the sum of the products.

\begin{align*}\begin{array}{rcl} && 5(6) + 5(3)\\ && 30 + 15\\ && 45 \end{array}\end{align*}

The value of the product of 5 times the sum of 6 plus 3 is 45.

#### Example 2

First, distribute the multiplier to each value in the parentheses.

Then, find the sum of the products.

The value of the product of 2 times the sum of 8 plus 1 is 18.

#### Example 3

First, distribute the multiplier to each value in the parentheses.

Then, find the sum of the products.

\begin{align*}\begin{array}{rcl} && 12(3) + 12(2)\\ && 36 + 24\\ && 60 \end{array}\end{align*}

The value of the product of 12 times the sum of 3 plus 2 is 60.

### Follow Up

Remember Josh at the yarn store?

Josh buys 10 bundles of red yarn, 8 bundles of green, 6 bundles of blue, and another 6 bundles of yellow for $3.49 each. Multiply the sum of bundles of yarn by $3.49 to find the total cost of the yarn.

First, write an expression to find the total cost of the yarn.

Then, distribute the multiplier to each value in the parentheses.

Then, find the sum of the products.

Josh spent $104.70 on yarn.

### Video Review

Khan Academy: The Distributive Property

https://www.youtube.com/watch?v=gl_-E6iVAg4

This video presents the distributive property from whole numbers to more complicated algebraic expressions.

The Distributive Property

https://www.youtube.com/watch?v=yiQ_q0oXVdU

### Explore More

Evaluate each expression using the distributive property.

- \begin{align*}10(9 + 7)\end{align*}