Basics of percent of change - with videos

The two videos below have to do with basics of percent of change, where you are given the initial and final quantities, and you have to calculate the the percent of change (percent change, percentage change).

The main formula I use is to calculate the DIFFERENCE in the quantities divided by the original quantity. Then this fraction is written as a decimal, and as a percent.





In the second video, I solve two word problems that involve percentage change - one having to do with percentage increase in area, and another where the price of a washer is discounted by 10%, then by another 10%, and we are asked the total discount percentage--yet the PRICE of the washer is NOT given!



Teachers - feel free to use these problems in your teaching!

I have recently been making lots of videos, aiming to produce full playlists for certain topics such as percent, decimals, and fractions. I also have many older videos on various topics. Click the image on the left to see my Youtube channel and see what I have uploaded thus far.