Tham khảo tài liệu 'symbols of addition 2', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ----------------------------------- THEA MATH REVIEW ---------------------------------------- Factors and Multiples Factors Factors are numbers that can be divided into a larger number without a remainder. Example 12 3 4 The number 3 is therefore a factor of the number 12. Other factors of 12 are 1 2 4 6 and 12. The common factors of two numbers are the factors that both numbers have in common. Examples The factors of 24 1 2 3 4 6 8 12 and 24. The factors of 18 1 2 3 6 9 and 18. From the examples above you can see that the common factors of 24 and 18 are 1 2 3 and 6. From this list it can also be determined that the greatest common factor of 24 and 18 is 6. Determining the greatest common factor GCF is useful for simplifying fractions. Example Simplify 72 . The factors of 16 are 1 2 4 8 and 16. The factors of 20 are 1 2 4 5 and 20. The common factors of 16 and 20 are 1 2 and 4. The greatest of these the GCF is 4. Therefore to simplify the fraction both numerator and denominator should be divided by 4. 16 4 4 20 4 5 Multiples Multiples are numbers that can be obtained by multiplying a number x by a positive integer. Example 5 X 7 35 The number 35 is therefore a multiple of the number 5 and of the number 7. Other multiples of 5 are 5 10 15 20 etc. Other multiples of 7 are 7 14 21 28 etc. 95 THEA MATH REVIEW The common multiples of two numbers are the multiples that both numbers share. Example Some multiples of 4 are 4 8 12 16 20 24 28 32 36 . Some multiples of 6 are 6 12 18 24 30 36 42 48 . Some common multiples are 12 24 and 36. From the above it can also be determined that the least common multiple of the numbers 4 and 6 is 12 since this number is the smallest number that appeared in both lists. The least common multiple or LCM is used when performing addition and subtraction of fractions to find the least common denominator. Example using denominators 4 and 6 and LCM of 12 -1- 4- - 1 3 . -5 21 4 6 4 3 6 2 JO 12 12 _ 13 12 11 Decimals The most important thing to .
