Percent decimals and fractions.notebook Percents, Decimals and Fractions Introduction to Percents Watch these 3 videos! February 18, 2015 3/4 75% 0.75 Khan Academy: 1. Describing the meaning of percent 2. Converting percents to decimals 3. Representing a number as a decimal, percent and fraction GOOD EXPLANATION: Math Goodies The meaning of percent (questions at end) Try this! Using the hundredths grids, shade in the following amounts. Write the percent, then equivalent representations using a decimal, proper fraction and simplified fraction. 50% 25% 75% 80% Practice Game: Math Goodies: A practice game! Worksheets for Extra Practice: Math Goodies: Worksheet for extra practice Math Goodies: The answers :) Percent decimals and fractions.notebook 1. To convert a fraction into a percentage, you need a denominator of 100. So how do we convert a fraction such as 10 into a percentage? 25 Two ways! A) Create an equivalent fraction where the denominator is 100. 10 = ? 25 100 * 25 x 4 = 100 SO multiply the numerator by the same number. * 10 x 4 = 40 SO 40 = 40% 100 B) We can cross multiply! 10 = ? 25 100 * Multiply 10 x 100 = 1000 * Divide 1000 by 25 * Answer is 40, so 40 100 = 40% 2. How do I convert a decimal number to a percent? Let's start with 0.84. Look at the digits in the tenths and hundredths columns. We know there are 84 hundredths = 84/100 = 84%. But what about if our number is 0.841? What about the 1 thousandth? We include it as a decimal after the 84 = 84.1% This means it is 1 tenth of 1 hundredth (which is a thousandth). What if I have a whole number in my decimal? Look at this example: 1.84 We know we have 84 hundredths or 84%. The whole number 1 represents 100 hundredths, so 100 hundredths = 100%. So our percent becomes 184% 3. Let's convert a percent to a decimal number! Look at the following 11.6%. The 11 represents 11 hundredths or 0.11 The .6 represents 6 tenths of 1 hundredth (which is 6 thousandths) so our decimal becomes 0.116 February 18, 2015 Percent decimals and fractions.notebook February 18, 2015 Problems: 1. Place these fractions, decimals and percents on the number line. 25%, 1.55, 2/3, 75%, 1.9, 1 1/4 0 ½ 1 1 ½ 2 100% 2. Chris, Paul and Carla share the cost of renting a video game. • Chris pays 0.4 of the cost. • Paul pays 36% of the cost. • Carla pays the remainder of the cost. What fraction of the cost does Carla pay? a 6/25 b 9/25 c 19/25 d 24/25 3. Mr. Price’s class collects a total of 1943 pennies over a period of 4 weeks. Samantha brings 125 pennies each week. Approximately what percent of the total number of pennies collected does Samantha bring? a 10% b 25% c 50% d 75% 4. Jade goes shopping for a pair of jeans. She sees one pair that costs $39.99 with a 25% discount. A second pair costs $29.99 with a 15% discount. Which pair will cost her less? For help with discount problems, go to the following site: Practice Problems: Math Goodies: Real Life Problems Sale, Sale, Sale! Percent decimals and fractions.notebook Practice Problems! Textbook: page 369 #5, 7, 8, 9 page 370 A to F page 371 #5, 6 page 373 #5, 7 February 18, 2015