Lesson 11

Percentage Contexts

Lesson Narrative

In this lesson students are introduced to contexts involving markups, discounts, and commissions, and they continue to study contexts involving tax and tips.

Questions about rounding may naturally come up in this lesson. This lesson primarily involves dollar amounts, so it is sensible to round to the nearest cent (the nearest hundredth of a dollar). Percentages may be rounded to the nearest whole percent or fraction of a percent, depending on the situation.

Learning Goals

Teacher Facing

• Comprehend “interest,” “markup,” “markdown,” and “commission” as other contexts that involve adding or subtracting a percentage of the initial amount.
• Determine the original dollar amount before a markup, markdown, or commission.
• Explain (orally) how to calculate the new dollar amount after a markup, markdown, or commission.

Student Facing

Let’s learn about more situations that involve percentages.

Required Preparation

Print and cut up slips from the Card Sort: Percentage Situations blackline master. Prepare 1 copy for every 2 students. These may be re-used if you have multiple classes.

It is recommended that students be provided access to four-function calculators so that they can focus on reasoning about how numbers are related to each other, representing those relationships, and deciding which operations are appropriate (rather than focusing on computation.)

Student Facing

• I understand and can solve problems about commission, interest, markups, and discounts.

Building On