Copyright © Ed2Net Learning, Inc.1 Percent of Change Grade 7 Pre-Algebra

Copyright © Ed2Net Learning, Inc.2 Let’s warm up : Solve each proportion. Round to the nearest tenths: 1) Express 0.58% as a fraction. 3) Express 0.60 as Fraction. 2) Express 36 as a Percent ) Express 0.54 as percent.

Copyright © Ed2Net Learning, Inc. 3 We can show Fractions, decimal numbers and Percents with the help of a square grid model.  The 10 x 10 grid represents one whole. The grid in blue shade represents 24, 0.24 or 24%. 100 Let’s review what we did in the previous session

Copyright © Ed2Net Learning, Inc. 4 Convert Percent to Fraction STEP 1: Write down the percent divided by 100. To convert a Percent to a Fraction follow these steps: STEP 2: If the percent is not a whole number, then multiply both top and bottom by 10 for every number after the decimal point. STEP 3: Simplify (or reduce) the fraction A percent is a ratio that compares a number to 100. Therefore, you can write a percent as a fraction with a denominator Review

Copyright © Ed2Net Learning, Inc. 5 Express 62.5% as a fraction Write down the percent divided by 100. Multiply both top and bottom by 10 (because there is 1 digit after the decimal place) 62.5 = Simplify the fraction = 5 8 Answer = 5 8 Review

Copyright © Ed2Net Learning, Inc. 6 Convert Fraction to Percent STEP 1: Find a number you can multiply by the bottom of the fraction to get 100. To convert a Fraction to a Percent follow these steps: STEP 2: Multiply both top and bottom of the fraction by that number. STEP 3. Then write down just the top number with the "%" sign. Review

Copyright © Ed2Net Learning, Inc. 7 Express 3 as a Percent 16 We can multiply 16 by 6.25 to become = X6.25 Answer = 18.75% Review

Copyright © Ed2Net Learning, Inc. 8 Convert Decimal to Fraction STEP 1: Write down the decimal divided by 1. To convert a Decimal to a Fraction follow these steps: STEP 2: Multiply both top and bottom by 10 for every number after the decimal point. STEP 3. Simplify (or reduce) the fraction Review

Copyright © Ed2Net Learning, Inc. 9 Express 0.75 as Fraction 0.75 = 1 75 = 100 X100 Answer = Write down 0.75 as : Multiply both top and bottom by ÷ Review

Copyright © Ed2Net Learning, Inc. 10 Convert Decimal to percent STEP 1: Write down the decimal number. STEP 2: Move the decimal point two places to the right. To convert a Decimal to a percent follow these steps: STEP 3. Add a percent sign. Review

Copyright © Ed2Net Learning, Inc. 11 Express as percent Write down the decimal number. Move the decimal point two places to the right. = 62.5%Add a percent sign. Answer = 62.5% Review

Copyright © Ed2Net Learning, Inc. 12 Today we will discuss about Percent of Change The percent a quantity increases or decreases from its original amount is the percent of change. percent of change = amount of change original amount When the amount increases the percent of change is a percent of increase. When the amount decreases the percent of change is a percent of decreases.

Copyright © Ed2Net Learning, Inc. 13 There are two ways to calculate a percentage change. Method 1: STEP 1: Calculate the difference (subtract one value form the other). STEP 2: Divide that Difference by the old value (you will get a decimal number). STEP 3: Convert that to a percentage (by multiplying by 100 and adding a "%" sign)

Copyright © Ed2Net Learning, Inc. 14 Method 2: STEP 1: Divide the New Value by the Old Value. STEP 2: Convert that to a percentage (by multiplying by 100 and adding a "%" sign) STEP 3: Subtract 100% from that.

Copyright © Ed2Net Learning, Inc. 15 Find the percentage change from $120 to $135. Method 1:Method 2: Step 1: Calculate the difference. $135 - $120 = $15 Step 2: Divide that Difference by the old value. $15 = $120 Step 3: Convert that to a percentage x 100 = 12.5% Step 1: Divide the New Value by the Old Value. $135 = $120 Step 2: Convert that to a percentage x 100 =112.5% Step 3: Subtract 100% from that % - 100% = 12.5% The percentage of change is 12.5%

Copyright © Ed2Net Learning, Inc. 16 Calculate the percentage increase from 4 to 7.5. Method 1:Method 2: Step 1: Calculate the difference = 3.5 Step 2: Divide that Difference by the old value. 3.5 = Step 3: Convert that to a percentage x 100 = 87.5% Step 1: Divide the New Value by the Old Value. 7.5 = Step 2: Convert that to a percentage x 100 = % Step 3: Subtract 100% from that % - 100% = 87.5% The percentage of increase is 87.5%

Copyright © Ed2Net Learning, Inc. 17 BREAK

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Copyright © Ed2Net Learning, Inc. 19 Assignments State whether each percent of change is a percent of increase or percent of decrease. Then find the percent of increase or decrease. 1) Old : 142 pounds ; New : 114 pound 2) Old : 425 people ; New : 480 people 3) Old : 14.5 liters ; New : 1.5 liters 4) Old : $228 ; New : $251

Copyright © Ed2Net Learning, Inc. 20 State whether each percent of change is a percent of increase or percent of decrease. Then find the percent of increase or decrease. 5) Old : 29.5 ounces ; New : 26.5 ounce 6) Old : 124 minutes ; New : 137 minutes 7) Old : $106 ; New : $250 8) Old : points ; New : points

Copyright © Ed2Net Learning, Inc. 21 9) Find the percent of decrease from 1,500 to ) Find the percent of increase from 38 to 95.

Copyright © Ed2Net Learning, Inc. 22 Today we discussed about Percent of Change The percent a quantity increases or decreases from its original amount is the percent of change. percent of change = amount of change original amount When the amount increases the percent of change is a percent of increase. When the amount decreases the percent of change is a percent of decreases. Very Good! Let's Review

Copyright © Ed2Net Learning, Inc. 23 There are two ways to calculate a percentage change. Method 1: STEP 1: Calculate the difference (subtract one value form the other). STEP 2: Divide that Difference by the old value (you will get a decimal number). STEP 3: Convert that to a percentage (by multiplying by 100 and adding a "%" sign) Review

Copyright © Ed2Net Learning, Inc. 24 Method 2: STEP 1: Divide the New Value by the Old Value. STEP 2: Convert that to a percentage (by multiplying by 100 and adding a "%" sign) STEP 3: Subtract 100% from that. Review

Copyright © Ed2Net Learning, Inc. 25 Find the percentage change from $120 to $135. Method 1:Method 2: Step 1: Calculate the difference. $135 - $120 = $15 Step 2: Divide that Difference by the old value. $15 = $120 Step 3: Convert that to a percentage x 100 = 12.5% Step 1: Divide the New Value by the Old Value. $135 = $120 Step 2: Convert that to a percentage x 100 =112.5% Step 3: Subtract 100% from that % - 100% = 12.5% The percentage of change is 12.5% Review

Copyright © Ed2Net Learning, Inc. 26 Calculate the percentage increase from 4 to 7.5. Method 1:Method 2: Step 1: Calculate the difference = 3.5 Step 2: Divide that Difference by the old value. 3.5 = Step 3: Convert that to a percentage x 100 = 87.5% Step 1: Divide the New Value by the Old Value. 7.5 = Step 2: Convert that to a percentage x 100 = % Step 3: Subtract 100% from that % - 100% = 87.5% The percentage of increase is 87.5% Review

Copyright © Ed2Net Learning, Inc. 27 You have done a nice job. See you in the next session.