Chapter 4

Fractions, Decimals, and Percent

Reducing Fractions

• Prime Factors Prime factors are prime numbers Prime numbers can only be evenly divided by themselves and one

For Example•1, 2, 3, 5, 7, 11, 13•‘4’ isn’t prime because it can be evenly divided by 1, 2, & 4

Example 4–2 Find the prime factors of 8, 9. 36, and 150

Bill R. Deem and Tony ZanniniElectronics and Computer Math, Eighth Edition

Copyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458

All rights reserved.

Reducing Fractions

Multiplying Fractions

Dividing Fractions

•Simple rules Invert Divisor and follow rules for multiplying fractions

Example•3/8 divide 3/4

•Yields 3/8 * 4/3 = 1/2

Adding/Subtracting Fractions

• After you have common denominators: Add/subtract numerators Reduce answer

• Changing fractions to have common denominators Find Least Common Denominator

•Factor each denominator to prime terms•Determine Max number of times a prime factor appears in any one term

Example 4–12 Find the LCM of 50, 60, and 80.

Bill R. Deem and Tony ZanniniElectronics and Computer Math, Eighth Edition

Copyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458

All rights reserved.

Adding/Subtracting Fractions

• Changing fractions to have common denominators Find Least Common Denominator

• Multiple the resulting Prime factors found in previous step. This is the Least Common Multiple (LCM)– use as common denominator

For each fraction multiply both numerator and denominator by factor needed to make denominator = LCM

• Then treat as fraction with common denominator

Bill R. Deem and Tony ZanniniElectronics and Computer Math, Eighth Edition

Copyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458

All rights reserved.

Adding/Subtracting Fractions

Bill R. Deem and Tony ZanniniElectronics and Computer Math, Eighth Edition

Copyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458

All rights reserved.

Adding/Subtracting Fractions

Fractions, Decimals, and Percent

• Add/Sub of Mixed Number Change all to Improper Fractions Perform Add/Sub as for proper fractions

If answer is still an improper fraction – change to a mixed number

• Multiply/Divide Mixed numbers Change all to Improper Fractions Perform indicated operations as for proper fractions

Fractions, Decimals, and Percent

• Multiply/Divide Mixed numbers If answer is still an improper fraction – change to a mixed number

• Fraction to Decimal Perform indicated division

• Decimal to Percentage Multiply decimal by 100 and add ‘%’ sign