Writing a Percent Markup Expression

The video tutorial teaches how to write a percent markup expression using a double number line. It explains the concept of markup as a percentage added to the cost of an item to ensure profit. The tutorial uses a double number line to illustrate the relationship between percents and decimals. It guides students through calculating a 30% markup using algebraic expressions, represented as 1.30x, where x is the cost of an item. The video concludes by showing how to apply this markup to determine the selling price of t-shirts for a class fundraiser.

Describe how a double number line can be used to understand percent markup.

What does the expression 1.30x represent in the context of the t-shirt sales?