- Fifth Grade
- 65 minutes
- Standards: 5.OA.A.2
Help your students create a basis for future math classes with this lesson that teaches children about math expressions and how they can interpret them.
Students will interpret numerical expressions without solving them and write simple expressions.
Introduction (5 minutes)
- Review the commutative property of multiplication and the order of operations.
- Teach students that expressions are a series of numbers and symbols, such as +, -, x, and ÷, without an equal sign.
- Write the expression 5 (4 + 3) on the board.
- Tell students that when that expression is worked out it is called an evaluation of the expression.
- The expression equals 35, therefore 5 (4 + 3)= 35 is the equation.
- Tell students that the expression 5 (4 + 3) is 5 times larger than the expression (4 + 3).
- Let students know that today they are going to evaluate the relationship between expressions and write their own expressions to evaluate.
Explicit Instruction/Teacher Modeling (10 minutes)
- Write the steps “double five and then add 50” on the board.
- Ask students to write an expression for the steps above.
- They should write (5 x 2) + 50 or 5+5+50.
- Write the expression "6 (10x10)" on the board.
- Ask students to describe, in writing, how the expression relates to (10x10).
- They should write that the expression 6 (10x10) is 6 times larger than the expression (10x10).
- Choose volunteers to create their own expressions like the two you just modeled and explain them.
- Guide students through the process of evaluating their expressions orally.
Guided Practice/Interactive Modeling (10 minutes)
- Allow students to form pairs or small groups.
- Pass out the Welcome to Mummy’s Market worksheet.
- Advise students that they should work with a partner or group to write an expression and evaluate the expressions.
- Remind students to refer back to their notes from the models you provided.
Independent Working Time (20 minutes)
- Pass out blank paper.
- Tell students that they are going to work alone to create their own expressions and evaluate the relationships between the numbers just like they have been practicing.
- Students may need an example to get them started. Example: Write an expression in words, such as "divide 144 by 12, and then subtract 20." Students should write (144 ÷ 12) – 20 and go on to write that the expression (144 ÷ 12) – 20 is 20 less than (144 ÷ 12).
- Enrichment: Advanced students can evaluate expressions that contain fractions, decimals, etc.
- Support: Struggling students can use the Multiply It! worksheet during the guided practice.
Related Books and/or Media
Assessment (15 minutes)
- Pass out the Express Yourself assessment.
- Advise students to use a blank sheet of paper to show their work.
- Remind them that they must follow the directions and answer the questions completely.
Review and Closing (5 minutes)
- Write the following expression on the board: (200 ÷ 10) x 0.5.
- Have students identify the expressions and equation.
- Then have students evaluate the expression without calculating it: (200 ÷ 10) x 0.5 is ½ of (200 ÷ 10).
- Ensure that students can create a word problem or steps for this equation: divide 200 by 10 then multiply by a half.