Apply a Discount before a Tax
A discount removes a percent of the original price.
About 20 minutes, plus any extended practice
Open lesson 1Percent Changes, Reverse Percents, and Simple Interest
A percent is a ratio per hundred, but its base quantity matters. Successive percent operations act on successive amounts; reverse problems recover the original base rather than simply adding back a percentage.
Before you begin
- Convert percents to decimals; multiply decimals; solve a one-step multiplication equation.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Identify the Base of Percent Increase
Percent change compares the change amount with the original amount.
About 20 minutes, plus any extended practice
Open lesson 2Recover an Original Amount
A reduced amount is the surviving percent of an unknown original.
About 20 minutes, plus any extended practice
Open lesson 3Separate Interest from a Total Balance
Simple interest is proportional to principal, time, and rate.
About 20 minutes, plus any extended practice
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.
Topic references
- California CCSS mathematics topic reference: topic reference — Percent Changes, Reverse Percents, and Simple Interest
These references informed the topic selection. They do not certify complete standards alignment.