Percentage Increase and Decrease with Equations

Warmup

Activity #1

Draw Diagram to Represent Percentage Change.

The number of miles driven this month was a 30% decrease of the number of miles driven last month.

• Draw a diagram to represent the situation.

The amount of paper that the copy shop used this month was a 25% increase of the amount of paper they used last month.

• Draw a diagram to represent the situation.

Activity #2

Finding Percentage Change.

•  Select whether you want a percentage increase or decrease by clicking on the appropriate box. ​A slider is introduced.
• Check the “Question” box if you wish to use a provided question. ​
• Read the question and type in the amount representing 100% in the “Total” box. ​The amount that is given in the problem.
• In the “percentage change” box, type in the required value given in the problem, and press the Enter key.
• Move the slider to the right to “shift” this amount to the other end of the bar. ​
• Check the “Show change” box to highlight the new amount. ​
• Check the “Answer” box if you used the provided question to see the answer to the problem. ​
• Click on the button to get a new question. Take note that, regardless of which choice you made at the beginning, the same steps will apply.

Activity #3

Demonstrate Percentage Increase and Decrease.

• Check the first box to start with percentage increase.
• Move the slider to see percentage increase on the bar and how it is found.
• Uncheck the box and check the second box to observe percentage decrease. If you run out of screen space, use your mouse to enable zoom.
• Move the slider to see percentage decrease on the bar and how it is calculated.

Challenge #1

An astronaut was exploring the moon of a distant planet, and found some glowing goo at the bottom of a very deep crater. She brought a 10 gram sample of the goo to her laboratory. She found that when the goo was exposed to light, the total amount of goo increased by 100% every hour.

Challenge #2

Challenge #3

In a video game, Clare scored 50% more points than Tyler. If c is the number of points that Clare scored and is the number of points that Tyler scored, which equations are correct?

Quiz Time

https://www.ixl.com/math/grade-7/percent-of-change-find-the-original-amount-word-problems