## Tuesday, February 1, 2011

### Justin Lorenzo's Final Percent Post

Percent means out of 100. It is also another name for hundredths and can also be expressed as fractions and or decimals.

4.1 Representing Percents Key Ideas : Shade squares on a grid of 100 squares called a hundred grid to represent a percent. A completely shaded grid represents 100%. If you shade more than one grid, that represents a percent greater than 100%. To represent a fractional percent between 0% and 1%, you have to shade part of one square. Also, to represent a fractional percent greater than 1% you have to shade squares from the hundred grid to show the whole number, then shade part of a square from the grid to show the fraction.

4.2 Fractions, Decimals and Percents Key Ideas : Percents can also be written as decimals or a fractions.

Ex. 1/2 = 0.50 = 50%

4.3 Percent of a Number Key Ideas : You can use mental math strategies such as doubling, halving, and dividing by 10 to find the percents of some numbers. Write the percent as a decimal and then multiply by the number to calculate the percent of a number.

eg. 12 ½ % of 50 = 0.125x50 = 6.25

4.4 Combining Percents Key Ideas : Adding percents can be used to solve problems.

Eg. Add combined percent with original number: 25% of 100 = 25. 25 + 100 = 125

Eg. Multiply the number by a single percent greater than 100: 125% of 100 1.25 x 100 = 125 Percents of percents can be used to determine amounts that result from consecutive percent increases or decreases.