Lesson 5.5 and 5.6. Changing Fractions to Decimals and Decimals to Fractions

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1 Lesson 5.5 and 5.6 Name: Changing Fractions or Decimals to Percents 1) Key in the fraction or decimal. 2) Hit the 2 nd key, then the % key, then enter. Changing Fractions to Decimals and Decimals to Fractions 1) Key in the fraction or decimal. 2) Hit the <> key, which is just above the enter key. Then hit enter. NOTE: The <> key converts fractions to decimals, or decimals to fractions whichever one is entered. This is a function that is used often in math, so it has its own calculator key. Changing Percents to Decimals 1) Key in the percent by keying in the number first, following by the % key. If it s 25 your calculator should display it as 25%. 2) Hit the <> key and it will convert the percent to a fraction. Hit the <> key again to convert it to a decimal. Finding the Percent of a Number Example: What is 25% of 200? 1) Key in 25, then the % sign to display 25%. 2) Multiply it by 200, then hit enter. NOTE: You can do the same without even hitting the x key. Your calculator will multiply if there is no sign. So you can just key in 25%, then 200, then enter. Discount and Sales Price Discount: The part of the original cost of something that you DON T have to pay. It s the amount that is taken away from the original cost of an item. It is often shown as a percent. Sale Price: The sale price is the cost of something after the discount is subtracted from the original price. Example 1: An item originally costs $200. It is on sale with a 20% discount. What is the sale price? TO SOLVE: First find 20% of 200 by using the directions above; Finding the percent of a number. You ll find that it s $40. Then subtract the $40 from the original price of $200. The sale price is $160. Example 2: A boat sells for $30,000, but is on sale with a discount of 15%. What is the sale price of the boat? TO SOLVE: First find 15% of 30,0000 which is $4,500. Then subtract the $4,500 from $30,000 to get $25,500 which is the sale price.

2 Using the Percent Equation This is the Percent Equation: a = p b 100 There are 3 types of problems that can be solved using the percent equation. Example 1 3 is what percent of 8? Since the question asks what percent, the p for percent stays the same. The 3 replaces a, and the 8 replaces b. The equation would be written like this: 3 = p To solve, multiply 3x100 to get 300, then divide by 8 to get So, 3 is 37.5% of 8. Example 2 What is 20% of 300? Since the percent is given as 20, 20 replaces the p. The of 300 is a clue that the 300 should replace the b. So the equation would be written like this: a = 20 To solve, multiply 300x20 to get 6,000, then divide by 100 to get So, 20% of 300 is 60. Example 3 12 is 20% of what number? Since the percent is given as 20, 20 replaces the p. The 12 is gives us a clue that the 12 should replace the a. So the equation would be written like this: 12 = 20 To solve, multiply the 12x100 to get 1,200, then divide by 20 to get 60. b 100 So, 12 is 20% of 60.

3 Lesson 5.5 HW Use a CALCULATOR to complete the table below with the missing decimals, fractions, and percentages. Use a percent sign for the percentages..56 Decimal Fraction/Mixed # Percent (in simplest form) % %.04.5% CHALLENGE: Find the LARGEST 6-digit whole number with these conditions: The MAD of the Largest 3 digits only is twice the MAD of the smallest 3 digits. The 3 largest digits must all be larger than any of the 3 smallest digits.,

4 5.6 HW Name: USE A CALCULATOR! Part 1: Discount of a number 1) Find 30% of ) Find 40% of ) Find 5% of ) Find.5% of 10. 5) Find 8% of ) Find 50% of 325. Part 2: Finding Sales Price 7) A video game normally sells for $120. It is now selling with a 15% discount. What is the sale price of the game? $ 8) A new house was first sold for $350,000. It is now selling with a 30% discount. What is the sale price of the house? $ 9) A sweater sells for $45. It is now on sale for 50% off. What is the sale price of the sweater? $ 10) A mansion on the beach sells for one million dollars. It is being discounted by 35%. What is the sale price of the mansion? $ Challenge (Optional): A product is being sold with a 22% discount. The sale price is $77 less than the original price. What is the original price? $

5 5.6 HW2 Name: Use the equation: a = p to solve each problem below. B 100 Equation Solution 1) 15 is what percent of 60? = % 2) What percent of 80 is 24? = % 3) 32 is 75% of what number? = 4) What is 35% of 300? = 5) 48 is 40% of what number: = 6) What percent of 200 is 8? = % 7) 16 is what percent of 160? = % 8) What is 88% of 500? =