Fractions to Decimals

Chapter 5: Fractions, Decimals, and Percents Study Guide

Fractions to Decimals  When you have a fraction that can be written as a “friendly fraction” (a fraction that has a power of ten in the denominator), you can use the numerator as the digits for the decimal.

5 37 = 5.37 9/10 =______10/25 = 40/100 = .4 2/5 = ______100  When you have fractions that cannot be written as “friendly factions” you must divide the numerator by the denominator. So….you must do long division!  Remember: The three steps to get set up are: 1. Write a decimal next to the numerator 2. Bring up your decimal 3. Write in your place holder 0

5/16 = 5/12 =

Remainder

Decimals to Fractions  To write a terminating decimal as a fraction, the digits of decimal are the numerator, and the denominator is the place value of the last digit.  REMEMBER TO WRITE THE FRACTION IN SIMPLEST FORM.

.567 = 567/1000 3.67 = 3 67 .25 = ______.9 = ______100

Decimals to Percents  D2P: Move your decimal place to the right two places.  This is because you are really MULTIPLYING BY 100.

.56 = 56% 2.39 = 239% .45 = ______1.05 = ______

Percents to Decimal  P2D: move your decimal to the left two places  You are really DIVIDING BY 100. 67% = .67 103% = 1.03 89% = ______50% = ______Fractions to Percents  If a fraction can be written with a denominator of 100, then the numerator is the percent.  If the fraction cannot be written with a denominator of 100, then you must convert it to a decimal by long division and then a percent.

4/25 = 16/100 = 16% 15/20 = ______= ______

Percents to Fractions  The given percent is the numerator and the denominator is 100. (Percents are always compared to 100.)  You must put the fraction in lowest terms.

59% = 59/100 72% = 72/100 = 18/25 18% = ______

COMPARING DECIMALS, PERCENTS & FRACTIONS

Just Decimals  You must know about PLACE VALUE because you will be asked to read decimals in “math language”  You must be able to order decimals: DRAW YOUR COLUMNS to compare each place value one at a time

Order from least to greatest: .285, .28, 6.27, 6.29, 6.08 Line up your decimal so you can compare your place value:

.285 .28 .28, .285, 6.08, 6.27, 6.29 6.27 6.29 6.08

Order from greatest to least: 7.56, 7.5, 7.056, 7.34 Just Fractions  Always use the BENCHMARK strategy first. (Compare to 0, ½, and 1)  If that doesn’t help, draw a picture, convert to decimals or use the LCD

6 8 9 12 55 14 9 11 10 13 100 20

Comparing All Three At Once!!!!! Either:  Make them all a percent  Make them all a decimal  Make them all a fraction  USING BENCHMARKS HERE CAN BE HELPFUL

Order from least to greatest: 4/5, 55%, .45 2/6, .25, 30% Show work: Show work: 4/5 = .60 55% = .55 .45 = .45 .45, 55%, 4/5

IMPORTANT NOTES:  It would be extremely helpful to know all the fractions on your blue reference sheet.  You will also be asked to write fractions and percents represented by pictures.  For extra practice you can play any fraction, decimal, and percent game on the internet. Here are a few: Comparing Fractions, Decimals, and Percents:  http://www.toonuniversity.com/flash.asp?err=198  http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/com paring/comparingall3/game.shtml  http://www.mathgoodies.com/lessons/vol4/challenge_vol4.html  Comparing Fractions: http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/fract ions/comparingfractions/game.shtml