Percentage Increase and Decrease

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Last updated: 8/16/2025

Key Concepts

  • A percentage increase means adding a certain percentage to the original value.
  • A percentage decrease means subtracting a certain percentage from the original value.
  • Formula: New Value = Original Value × (1 ± percentage as a decimal).

Skills Covered

  • Calculate the increased or decreased value after a percentage change.
  • Work with real-world applications (e.g., population growth, price discounts).

Example Problems

  • A population of 1,000 increases by 20%. What is the new population?
  • A shirt originally costs $50 and is 30% off. What is the sale price?
  • The price of a stock decreased by 15% from $200. What is the new price?

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