Evaluate the expression

Here you will learn how to evaluate the expression given a value for the variable.

Students will first learn how to evaluate the expression as part of expressions and equations in 6th grade.

Every week, we teach lessons on evaluating the expression to students in schools and districts across the US as part of our online one-on-one math tutoring programs. On this page we’ve broken down everything we’ve learnt about teaching this topic effectively.

What does it mean to evaluate the expression?

To evaluate the expression means to substitute the variable(s) of a polynomial with given value(s).

If x=6, what is the value of 6x+1?

Substitute 6 for x and follow the order of operations:

The same process can be used when there is more than one variable.

If c=2 and t=4, what is the value of 3 \, (c-1)+t^2?

Substitute 2 for c and 4 for t , and follow the order of operations:

\begin & 3(2-1)+4^2 \\\\ & =3(1)+4^2 \\\\ & =3(1)+16 \\\\ & =3+16 \\\\ & =19 \end

What does it mean to evaluate the expression?

Common Core State Standards

How does this relate to 6th grade math?

• Grade 6 – Expressions and Equations (6.EE.B.5)
  Understand solving an equation or inequality as a process of answering a question: which values from a specified set, if any, make the equation or inequality true? Use substitution to determine whether a given number in a specified set makes an equation or inequality true.

How to evaluate the expression

In order to evaluate the expression:

1. Substitute each variable with its given value.
2. Evaluate using the order of operations.

[FREE] Evaluate The Expression Worksheet (Grade 6 and 7)

Use this worksheet to check your 6th grade and 7th grade students’ understanding of evaluate the expression. 15 questions with answers to identify areas of strength and support!

[FREE] Evaluate The Expression Worksheet (Grade 6 and 7)

Use this worksheet to check your 6th grade and 7th grade students’ understanding of evaluate the expression. 15 questions with answers to identify areas of strength and support!

Evaluate the expression examples

Example 1: one step, one variable

Evaluate 4m when m=35.

1. Substitute each variable with its given value.

Remember, numbers and letters written next to each other are being multiplied:

2 Evaluate using the order of operations.

There is only one step, multiply.

Example 2: two steps, one variable

Evaluate 3 \, (h+22) when h=9.

Substitute each variable with its given value.

Evaluate using the order of operations.

\begin & 3(9+22) \\\\ & =3(31) \quad \quad \text < *Remember, >3 \, (31) \text < is the same as >3 \times 31 \\\\ & =93 \end

Example 3: two steps, one variable, and a fraction

Evaluate 50-\cfrac when m=20.

Substitute each variable with its given value.

Evaluate using the order of operations.

Because the numerator is larger than the denominator, the fraction can be simplified with division: \, \cfrac=20 \div 2.

Example 4: two steps, two variables

Evaluate 11x-2y , when x=5 and y=6.

Substitute each variable with its given value.

11 \times 5-2 \times 6

Evaluate using the order of operations.

\begin & 11 \times 5-2 \times 6 \\\\ & =55-2 \times 6 \\\\ & =55-12 \\\\ & =43 \end

Example 5: three steps, two variables, and a mixed number

Evaluate 5(3+p)-r , when p=11 and r=22 \, \cfrac \, .

Substitute each variable with its given value.

Evaluate using the order of operations.

\begin & 5(3+11)-22 \cfrac \\\\ & =5(14)-22 \cfrac \quad \quad \text < **Remember >5(14) \text < is the same as >5 \times 14 \\\\ & =70-22 \cfrac \\\\ & =47 \cfrac \end

Example 6: three steps, two variables, and an exponent

Evaluate a^3(n-7) , when a=3 and n=9.

Substitute each variable with its given value.

Evaluate using the order of operations.

\begin & 3^3(9-7) \\\\ & =3^3(2) \quad \quad \text < **Remember >3^3 \text < is the same as >3 \times 3 \times 3 \\\\ & =27(2) \quad \quad \text < **Remember >27(2) \text < is the same as >27 \times 2\\\\ & =54 \end

[FREE] Evaluate The Expression Worksheet (Grade 6 and 7)

Use this worksheet to check your 6th grade and 7th grade students’ understanding of evaluate the expression. 15 questions with answers to identify areas of strength and support!

[FREE] Evaluate The Expression Worksheet (Grade 6 and 7)

Use this worksheet to check your 6th grade and 7th grade students’ understanding of evaluate the expression. 15 questions with answers to identify areas of strength and support!

Teaching tips for evaluating the expression

• A great way to build the conceptual knowledge needed for evaluating algebraic expressions is with hands-on representations, like algebra tiles or other manipulatives. It is also a good idea to start with whole number coefficients and constants, as they are easier for students to make sense of and typically work better with manipulatives.

• While “finding the answer” is an important part of this skill, it should not be the only focus. At this stage in their development, students are still building foundational ideas about algebraic expressions, so it is important to draw attention to all parts of the process and help them make mathematical connections. Give students time to find and explore different numbers in the solution set, and encourage them to look for patterns between an expression and its solution set.

• Use expressions that come from real life scenarios when possible. This can help students think more deeply about how and why a solution set fits a given algebraic expression. For example, if the expression 8h is created to represent how many hotdogs there are based on h, the number of packets, students use the scenario to make connections between the expression and its solution set.

Easy mistakes to make

• Not following order of operations (pemdas)
  The order of operations should always be used to evaluate the expression. For any given expression, this means solving within the parentheses, then the exponents, then multiplying or dividing from left to right, and finally adding or subtracting left to right. Not following this order will give the incorrect answer.

For example,
Evaluate x -3y when x=10 and y=2.

Confusing the values of the variables when there is more than one
Always pay attention to which value is assigned to each variable. Mixing them up will result in a different answer.

For example,
Evaluate 5x+y when x=3 and y=4.

Confusing the meaning of a number next to a parenthesis
Remember in an expression when there is a number next to parenthesis, the operation is multiplication.

For example,
If 4 \, (k+10), evaluate the expression when k=1.

Related algebraic expressions lessons

• Algebraic expression
• Combining like terms
• Simplifying expressions
• Expanding expressions
• Equivalent expressions
• Polynomial