1. Chapter 4 Fractions, Decimals, and Percent

2. 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

3. Example 4–2 Find the prime factors of 8, 9. 36, and 150 Bill R. Deem and Tony Zannini Electronics and Computer Math, Eighth Edition Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

4. Reducing Fractions Steps  Convert numerator and denominators to prime factor  Cancel common factors  For Example 15/81 = 3*5/3*3*3*3 Yields 3*5/3*3*3*3 = 5/27

5. Multiplying Fractions Steps  Cancel common factors in both numerator & denominator  Multiply remaining factors for both numerator and denominator  Example ¾ * 2/3 * 5/6 = 3*2*5/4*3*6 Yields 2*3*5/2*2*3*2*3 = 5/12

6. 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

7. 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

8. Example 4–12 Find the LCM of 50, 60, and 80. Bill R. Deem and Tony Zannini Electronics and Computer Math, Eighth Edition Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.

9. 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

10. Bill R. Deem and Tony Zannini Electronics and Computer Math, Eighth Edition Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Adding/Subtracting Fractions

11. Bill R. Deem and Tony Zannini Electronics and Computer Math, Eighth Edition Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Adding/Subtracting Fractions

12. 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

13. 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