Presentation on theme: "9-1: Relating Fractions, Decimals, and Percents"— Presentation transcript:
1 9-1: Relating Fractions, Decimals, and Percents IWBAT convert a percent to a fraction or decimal and convert a fraction or decimal to a percent.
2 Vocabulary Percent – A special ratio that compares a number with 100 Percent means “per hundred”
3 Fraction to Decimal and Percent Fraction to PercentDivide the numerator by the denominatorPut the whole number in front of decimal, if neededConvert the fraction to a decimalMove the decimal to the right twiceAdd the % sign
7 Decimal to Fraction and Percent Decimal to PercentLook at the place value of the fractionPlace decimal over corresponding place valueSimplifyPut whole number in front if there is oneMove decimal right twiceAdd the % sign
9 9-2: Estimating PercentIWBAT estimate percents of numbers between 0% and 100% using multiples of 10% or fractions
10 Estimating Using Rounding Round the percent to the nearest 10%Round the number to the nearest 10sIf the number is less than 10, do not round itChange the percent to a decimalMultiply
11 Examples 1) Estimate 28% of 71 2) Estimate 9% of $19.99
12 Estimating Using Fractions Memorize the following common percent to fraction conversions:Round the whole number to the nearest 10sChoose the corresponding fractionMultiply10%20%25%33% or 34%50%66% or 67%75%90%1 101 51 41 31 22 33 49 10
13 Examples 1) 75% of 200 2) 39% of 600 3) 21% of 400 4) 26% of 19
14 9-3: Finding a Percent of a Number IWBAT use a proportion to set up percent problems and solve using cross products.
15 Percent Proportion Formula % 100 = 𝑝𝑎𝑟𝑡(𝑖𝑠) 𝑤ℎ𝑜𝑙𝑒 (𝑜𝑓)Think of problems as asking, “What is ?”
16 9-4: Is an Estimate Enough? IWBAT determine whether an estimate is a sufficient solution or whether an exact amount is needed.
17 9-5: Mental Math: Finding a Percent of a Number IWBAT use mental math to calculate percents of numbers
19 9-6: Solving Percent Problems Using Equations IWBAT write and solve percent equations.
20 Use the Percent Proportion Formula % 100 = 𝑝𝑎𝑟𝑡 (𝑖𝑠) 𝑤ℎ𝑜𝑙𝑒 (𝑜𝑓)Break up the problem and substitute into proper place in proportion formula
21 Write a proportion and solve. What number is 25% of 62?1) Break into sections.What number is25%Of 62= 𝑛 622) Substitute into formula3) Simplify, if possible4) Cross-Multiply
22 Examples 1) 15 is what percent of 75? 2) What number is 40% of 88? 3) What percent of 90 is 27?4) What is 120% of 360?5) 16 is what percent of 40?6) The 6th grade class is having a book sale. Their order included 300 novels. So far, 180 novels have been sold. What percent of the novels have been sold?
23 IWBAT writ and solve one-step linear equation involving percent 9-7: Write an EquationIWBAT writ and solve one-step linear equation involving percent
24 IWBAT find sales tax and total cost. 9-8: Finding Sales TaxIWBAT find sales tax and total cost.
25 VocabularyTip – A percentage of the total of your bill that you give for a serviceTax – A percentage of the total of your bill that you pay to the government
26 Finding Sales Tax and Total Cost You buy a soccer ball priced at $ If the rate of the sales tax is 6.5%, what is the total cost of the ball?1) Convert the percent to a decimal6.5% = 0.0652) Multiply the decimal by the price. This is the sales tax.14.69 ∙ 0.0653) Round UP to the nearest cent≈ 0.964) Add to the price to find the total cost$$15.65
27 ExamplesFind the sales tax and the total cost. Round the sales tax up to the nearest cent.Cost: $19 Rate of sales tax: 8%2) Cost: $412 Rate of sales tax: 6%3) Cost: $62.50 Rate of sales tax: 5.5%4) A basketball costs $30. The rate of sales tax was 5%. Find the total cost of the basketball.
28 IWBAT find discount and sales price. 9-9: Computing DiscountIWBAT find discount and sales price.
29 Finding the Discount and the Sale Price The Nature Shop had a 25% sale on kaleidoscopes. Michael bought one originally priced at $ How much did he pay on sale?1) Convert the percent to a decimal25% = 0.252) Multiply the decimal by the original cost. This is the discount.15.99 ∙ 0.253.99753) Round the discount DOWN to the nearest cent.≈ 3.994) Subtract the discount from the original price to find the sale price.$15.99 – 3.99$12.00
30 Examples 1) Regular price: $200 Rate of discount: 10% 4) Tommy bought two kaleidoscopes on sale for 20% off. If each kaleidoscope cost $29 before the sale, what did Tommy pay for both on sale?
31 9-10: Using the Interest Formula IWBAT use the simple interest formula to calculate interest and find the total amount earned or charged.
32 Vocabulary Interest – the amount of money paid for the use of money Investments, loans, savingsInterest Formula: I = prtI is interestp is principal (original amount deposited or borrowed)r is the rate of interest (the percent earned or charged)t is the time the money is in the account or is borrowed (measured in years)
33 Find the interest and total with interest You put $200 in a savings account earning 5.5% simple interest per year. What is the total you will have in your account after one year?1) Identify each variableI = ?p = $200r = 5.5% = 0.055t = 12) Rewrite the interest formulaI = prt3) Substitute. Solve the equation to find interest.I = prtI = 200(0.055)(1)I = $114) Add the interest to the principal$ = $211
34 Find the interest and the total with interest. ExamplesFind the interest and the total with interest.Principal: $6,000 Rate: 5% Time: 5 months2) Principal: $4,500 Rate: 18% Time: 6 months3) Principal: $500 Rate: 7.5% Time: 1 year4) You want to borrow $500,000 for 6 months at 12% interest. How much money will you owe the bank?