Percent increase and percent decrease describe the change in a quantity relative to its original amount: . The original value is the comparison base, so an increase by multiplies it by , while a decrease by multiplies it by ; this distinguishes percent change from percentage-point change and supports proportional reasoning in prices, discounts, tax, and other financial contexts. The scope is limited to single changes with familiar whole-number or decimal quantities, not successive, compound, or reverse-percent situations.
To find a percent increase or decrease:
The original amount is always the comparison base.
Example: A backpack’s price increases from 40$46$. What is the percent increase?
Step 1: Find the change.
The price increased by 6$.
Step 2: Compare the change with the original price.
Step 3: Convert to a percent.
The price increased by .
For a decrease, use the same steps: find how much the amount went down, divide by the original amount, and multiply by . An increase of multiplies the original by , while a decrease of multiplies it by , using as a decimal.
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