## Sunday, January 23, 2011

### Demvry's Final Percent Post

~ A percent means out of 100 and it's another name for hundreths which can be represented as a decimal or fraction
~Ex. 65% means 65 out of 100 or 65/100 or 0.65

4.1 Representing Percents

Key Ideas
To represent a percent you can use 100 grid charts. One shaded grid that has all the squares shaded in represents 100%. To show a percent that is larger than 100% you shade in more than one grid. To represent a percent between 0% and 1% you shade in a part of one square.

Fractional Percent - A percent that includes a portion of a percent.
Ex. 1/2%, 0.42%, 73/8%, 125 3/4%, 4.5%

4.2 Fractions, Decimals, & Percents

Key Ideas
Fractions, decimals, and percents can be used to represent numbers in various situations.
Percents can be written as fraction as decimals.
Ex. 1/2%=0.5% 0.5%=0.5/100 =0.005
150%=150/100
=1.5 or 11/2
423/4%=42.75% 42.75%=42.75/100 =0.4275

4.3 Percent of a Number

Key Ideas
You can use mental math strageties such as halving, doubling, and dividing by ten to find the percents of some numbers.
To calculate the percent of a number, write the percent as a decimal and then multiply by the number.
Ex.121/2% of 50 = 0.125 x 50 = 6.25
121/2%=12.5 = 0.125

4.4 Combining Percents

Key Ideas
Percents can be combined by adding to solve problems. 5% + 7% = 12%
To calculate the increase in a number,
~You can add the combined percent amount to the original number: 12% of 100 =0.12 x 100 = 12 100+12=120
~You can multiply the original number by a single percent greater than 100
Percents of percents can be used to determine amounts that result from consecutive percent increases or decreases.

Demvry's Percent Review Video

The video is kinda blurry so you might not see it very well.
The ending got cut off due to my computer.

http://www.mathgoodies.com/lessons/toc_vol4.html

The words might be oversized or undersized since it got lagged and became like that. If not ignore this.