Unit 7: Ratios, Percentages, and Proportional Reasoning

Day 22 of 30

Understand percent increase and decrease

K-2Mathematics

Content is AI-assisted and continuously improved through educator review

Learning Objective

I can understand percent increase and decrease.

Today's Lesson

Today we will learn how to understand percent increase and decrease. Math helps us solve problems and understand the world around us.

Percent means "out of 100." The symbol % stands for percent. For example, 50% means 50 out of 100, which is the same as 1/2 or 0.50. To find a percent, divide the part by the whole and multiply by 100. Percents are used everywhere: test scores (80%), discounts (25% off), and statistics (60% of students). Understanding percents helps you compare and understand data!

Let's break this down step by step so it's easy to understand. Follow along with the examples, and don't worry if it takes some practice to get the hang of it!

Remember: Making mistakes is part of learning. If something is tricky, try again, look at the examples, or ask for help.

Key Terms
Percent

A number out of 100

Problem

A question we need to solve

Activities
Instructions
1. Use objects or pictures to explore understand percent increase and decrease. 2. Try the examples together. 3. Solve practice problems. 4. Check your work.
Materials Needed
  • Counters or objects
  • Pencil
  • Practice sheet
Practice Problems
1

What is 50% of 20?

Hint: 50% means half.
2

Convert 1/4 to a percent.

Hint: 1/4 = 0.25, then multiply by 100.
3

A shirt costs $40. It is on sale for 25% off. How much is the discount?

Hint: Find 25% of $40.

Teaching Tip

For younger learners: Use concrete objects and hands-on activities when teaching understand percent increase and decrease. Keep sessions short (10-15 minutes) and incorporate movement or songs when possible.

AI Tutor

Get instant help with this lesson. Ask questions and receive personalized explanations from your AI tutor.