Percent Increase & Decrease
Prices drop. Towns grow. Scores change. Let's find out how much.
Tap a story below to start. Already a pro? Jump to practice.
1
Where Do You See Percent Change?
Pick a story. Make a guess, then see the answer.
Your guess
2
What Is a Percent Change?
It compares the new amount with the original, where you started. More is a ▲ increase. Less is a ▼ decrease.
The Change Meter
Pick an original amount, then slide the change
The original amount is…
The big idea: percent change = × 100%. Always divide by the original, the amount you started with.
3
Finding the New Amount
Know the percent? Find the new amount two ways. They always match.
The Multiplier Machine
Choose an amount, a percent, and a direction
Start with…
Change it by…
Direction
▲ Add tax, tip, markup, grew, rose
▼ Subtract off, discount, sale, dropped, fell
Multiplier shortcut: 100% + 25% = 125%, so multiply by 1.25. 100% − 25% = 75%, so multiply by 0.75.
4
Finding the Percent Change
Know both amounts? Type them in and watch the steps.
The Percent Change Finder
Type two amounts or tap an example
Try an example
Always divide by the original. Tap Swap: 80 → 100 is a 25% increase, but 100 → 80 is only a 20% decrease.
5
Watch Out for These Traps
Trap 1: Up, then down. Back to the start?
The Round Trip Surprise
Go up by a percent, then down by the same percent
Start with…
Change by…
Why? The second percent is taken from a bigger amount, so it takes away more than you added.
Trap 2: Spot the mistake
Mistake Detective
Six students made a mistake. What went wrong?
6
Let's Practice
Three activities. Start with Up or Down?
Up or Down?
Choose the correct percent change. Check the direction and the percent!
Question 1 of 10Score: 0
Type It In
Type the new amount or the percent change.
Question 1 of 10Score: 0
Word Problems
Does it go up or down? Type your answer.
Problem 1 of 8Score: 0
What's next? Percents in Real Life: tips, sales, interest, and more.