Percent Grade 6

Copyright © Ed2Net Learning, Inc. Warm up 1. Express the ratio in their simplest form. a)35 : 50 Answer: a) 7 : 10 2. Fill in the gaps in each ratio, so that it becomes 3: 5when simplified. a) __ : 10 b) 18 : __ Answer: a) 6 b) 30 3. Express the following ratios as fractions. 1) 3 : 21 2) 0.5 : 1 ½ Answer: a) 1/7 b) 1/3 4. In a test containing 20 questions of 3 marks each and 15 questions of 2 mark each and 10 questions of 1 mark each, Susan got 65marks. Compare her marks with the total marks. Answer: 13: 20 Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Lets review what we have learned in the last leson 1. Ratio of two numbers X & Y(< >0) is X/Y (proper or improper fraction) written as X:Y. A ratio should be expressed in its lowest form 2. In the ratio X : Y, the term X is called the antecedent and the term Y is called the consequent 3. All equivalent ratios can be expressed in one common ratio in its lowest form 4. Ratios are said to be in proportion when they are equivalent Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Recap 5. In the proportion p:q =r:s, p & s are extremes and q & r are means and p*s=q*r 6. Two quantities are said to be in direct variation if they are related in such a way that when one increases(or decreases), the other also increases (or decreases) in such a manner that the ratio of the two remains the same. 7. The method of finding values by , first finding the value of one unit by division and then the value of the required number of units by multiplication is called the unitary method. Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Let’s get started A percent is a ratio of a number to 100. A percent can be expressed using the percent symbol %. y% = y 100 45 100 Example : 45% = Note: 45% can be expressed as the ratio 45:100 Copyright © Ed2Net Learning, Inc.

There are two main types of problems dealing with percents 1. The first type of problem is when the percent is given. 2.The second type of problem is when you are looking for the percent. Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Percent is given In these problems, you must change the percent to a decimal To change a percent to a decimal, divide the number by 100 This will move the decimal point two places to the left Example: Find 7% of 250. (Remember 7% = 0.07) Let x = the answer 0.07 (250) = x 17.5 = x Remember that the word "of" means to multiply” Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Example 30 is 15% of what number? (Remember 15%=0.15) Let n = the answer 30 = 0.15 n n = 200 Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Looking for a percent In these problems, you should put a variable over a 100. Example: 4 is what percent of 12? Let x = the percent. Writing this problem literally we would get: 4 = x% of 12. 4 = x/100 x 12 4/1 = 12x/100 12x = 4 x 100 x = 33 1/3% To change a percent to a decimal, divide the number by 100. Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. 1) Find 14% of 150 Solution: 14% can be expresses as The word “of” means multiply. so, you can write x 150 = 21 14% of 150 = 21 14 100 14 100 Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. 2) 46 is 20% of what number? Solution: Let x be the number. 46 is 20% of what number can be written as = 20% * x Solve for x 46 = 20/100 * x X = 230 Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. 3) 30 is what percent of 50? Let x be the percent. Writing the problem as equation of 30 = x% of 50 30 = x 50 = solve for x 50x = 30 * 100 multiply 100 on both sides 50x = 3000 Divide by 50 on both sides x = 60 % x 100 50x 100 Copyright © Ed2Net Learning, Inc.

Percent Increase and Decrease In order to solve problems with percentage of increase of decrease you need to use the formula shown below: = % increase or decrease Amount of increase or decrease Original amount Note: Multiply the fraction by 100 to get % increase or decrease Copyright © Ed2Net Learning, Inc.

Example Amount of increase or decrease Original amount 60 500 60 500 Maria's rent went up from $500 to $560. What is the difference of percent? Solution: Difference between the rent = $560 - $500 = $ 60 Use the formula, = = 100 x So, the difference of percent = 12% Amount of increase or decrease Original amount 60 500 60 500 Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Time for a break!!! Copyright © Ed2Net Learning, Inc.

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Copyright © Ed2Net Learning, Inc. Your Turn 1) Convert 45% to decimal. 0.45 2) Write the equivalent percent of 0.98 98% 3) Write the fraction of 15% 3/20 4) Convert fraction to percent: ½ 50% 5) If the price of a computer was decreased from $1000 to $750, by what percent was the price decreased? 25% Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. Your Turn 6) Convert 68% to decimal 0.68 7) Change the decimal to percent : 0.11 11% 8) Write the fraction of 47% 47/100 9) What is the percent of 1/25 ? 4% 10) A collectors' comic book is worth $120 in 1994, and in 1995 its value is $132. Find the percent increase? 10% Copyright © Ed2Net Learning, Inc.

Lets review what we have learned in our lesson Convert from Percent to Decimal: To convert a percent to decimal, divide by 100. It means moving the decimal point two places to the left. Example : 56% 56% = = 0.56 56% is equivalent to the decimal 0.56. 56 100 Copyright © Ed2Net Learning, Inc.

Convert from Decimal to Percent To convert a decimal to a percent, multiply by 100. It means moving the decimal point two places to the right. Example: 0.34 0.34 x 100 = 34 % 0.34 is equivalent to 34% Copyright © Ed2Net Learning, Inc.

Percent increase or decrease To find percent increase or decrease, use the formula = % increase or decrease Amount of increase or decrease Original amount Copyright © Ed2Net Learning, Inc.

Copyright © Ed2Net Learning, Inc. You did great today ! Be sure to practice what you have learned today! Copyright © Ed2Net Learning, Inc.