 # Decimals, Fractions, and Percent Review

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Decimals, Fractions, and Percent Review

Converting Fractions to Decimals
To convert a fraction to a decimal, divide the numerator by the denominator. You will get a decimal that terminates or repeats. If it repeats, place a bar (--- ) over the first number that repeats. Example 1: Convert 3/4 to a decimal 3/4 = 3÷4= 0.75 ( terminating decimal) Example 2: Convert 2/3 to a decimal 2/3= 2÷3= ( repeating decimal )

Converting Decimals to Percents
In order to convert a decimal to a percent, either multiply the decimal by 100 and write the percent sign (%), or move the decimal point two places to the right and write the percent sign (%). Example 1: Convert 0.20 to a percent 0.20x 100= 20% or 0.20= = 20% Example 2: Convert 4.00 to a percent 4x 100=400% or 4.00= =400%

Converting Percents to Decimals
When converting a percent to a decimal, either divide the percent by 100 and put the decimal point, or move the decimal point two places to the left and put the decimal point. Example 1: Convert 72% to a decimal 72%= 72÷ 100= 0.72 or = 0.72 Example 2: Convert 62.5% to a decimal 62.5%= 62.5÷ 100= or = 0.625

Copy and complete this chart
Percentage Decimal % .27 87% % .02 8% % .55 42% % .05 4% % .17 71% % .98 7%

Converting Fractions to Percents
To convert a fraction to a percent, change the fraction to a decimal ( by dividing the numerator by the denominator ). Then multiply the decimal by 100 and put a percent sign (%). Another way is to move the decimal point two places to the right and put a percent sign (%). Example 1: Convert 1/2 to a percent 1/2= 1÷ 2 = 0.50 0.50x 100= 50.00=50% or 0.50= = 50% Example 2: Convert 1/3 to a percent 1/3= 1÷3= 0.333 0.333x 100= =33.3% or 0.333= =33.3%

Another way to Convert Fractions to Percents
Make a proportion by putting a 100 under the percent. Then use cross products or mental math. Then add a percent sign. Example 1: Convert 1/5 to a percent Multiply the top and the bottom by 20 so x = 20% Example 2: Convert 3/25 to a percent Multiply the top and the bottom by 4 so x = 12%

Try these: Work out your percentage if you got 12 out of 25   Work out your percentage if you got 15 out of 25 Work out your percentage if you got 17 out of 20 A player scores 4 times out of 10 shots. What percentage did they make? 5. Calculate the score percentage if out of 15 shots 12 are successful 48% 60% 85% 40% 80%

Percent of Increase and Decrease

A percent change is an increase or decrease given as a percent of the original amount. Percent increase describes an amount that has grown and percent decrease describes an amount that has be reduced.

Percent of Increase The original cost of a CD was \$10. The same CD now costs \$15. It increased \$5. From \$10 to \$15 5 Change decimal to a percent = 0.5 10 50% increase

Percent of Decrease The original cost of a basketball was \$12. The same basketball now costs \$9. It decreased \$3. From \$12 to \$9 3 Change decimal to a % = 0.25 12 25% decrease

Finding Percent Increase and Decrease
Find each percent change. Tell whether it is a percent increase or decrease. Movie tickets went from \$8 to \$10 Simplify the numerator. Simplify the fraction. = 0.25 = 25% Write the answer as a percent. \$8 to \$10 is an increase, so a change from 8 to 10 is a 25% increase.

Finding Percent Increase and Decrease
Find the percent change. Tell whether it is a percent increase or decrease. Shoes went from \$75 to \$30 Simplify the fraction. Simplify the numerator. = 0.6 Write the answer as a percent. = 60% 75 to 30 is a decrease, so a change from 75 to 30 is a 60% decrease.

Practice: Worksheet