Math Example: Percents with Double Number Lines: Example 9

Topic

Ratios, Proportions, Percents

Description

This example illustrates how to solve for an unknown value using a double number line when given a part and its corresponding percentage. The image shows two horizontal number lines: the top line ranges from 0 to 100%, and the bottom line ranges from 0 to an unknown number x. The 40% mark on the top line aligns with 220 on the bottom line, visually demonstrating the process of finding x when 220 is 40% of x.

Double number lines are effective tools for teaching percentages as they provide a clear visual representation of the relationship between percentages and their corresponding numerical values. This collection of examples covers a range of scenarios, including finding the whole when given a part and a percentage that isn't as commonly used as 25% or 50%.

Offering multiple worked-out examples is essential for students to fully comprehend the concept of percentages using double number lines. Each example builds upon the previous one, progressively increasing in complexity and addressing different types of percentage problems. This approach enables students to identify patterns, develop problem-solving strategies, and gain confidence in applying the double number line method to various percentage calculations.

Teacher Script: "Now, let's examine this example where we need to find the whole when given a part and a percentage that isn't as common as 25% or 50%. We're told that 220 is 40% of some number. Using our double number line, we can visually represent this problem. Notice how 220 aligns with 40% on our percentage line. This helps us see that 220 is two-fifths of our unknown number. If 220 is two-fifths, what's one-fifth? That's right, it's 110. So what's the whole number? It's 550. This visual method helps us understand the relationship between percentages and the numbers they represent, even when dealing with less familiar percentages."

For a complete collection of math examples related to Percentages click on this link: Math Examples: Percents and Double Number Lines Collection.